Updated at 7:36 p.m. ET: LONDON -- A 26-year-old man was arrested Monday for the defacement of a Mark Rothko painting at London's leading contemporary art museum.

The incident took place on Sunday when a visitor to Tate Modern applied "a small area of black paint with a brush to the painting," to a painting titled "Black on Maroon" by the Russian-American artist.

The man arrested signed his name on the painting: Vladimir Umanets. He was placed in custody around 9 p.m. local time.

---

Photographs of the damage showed the text "VLADIMIR UMANETS '12, A POTENTIAL PIECE OF YELLOWISM'' scrawled on Rothko's 1958 canvas "Black on Maroon.

'Not art or anti-art'
Using a phone number posted on on the so-called "Yellowism" movement's website, a Reuters journalist spoke to a man answering to the name Vladimir Umanets who said he carried out the attack.

"I'm aware they (the police) will come at some point and arrest me,'' he told Reuters. "It was an artistic statement, but it was more about having the opportunity to speak about galleries and art."

A manifesto posted on the website reads: "Yellowism is not art or anti-art. Examples of Yellowism can look like works of art but are not works of art ... Art is forever developing 'diverse whole'. Yellowism is forever expaning 'homogeneous mass'."

Tim Wright who witnessed the incident described it as "surreal." He posted a picture on Twitter and described how "this guy calmly walked up, took out a marker pen and tagged it."

In another tweet, Wright wrote: "Very bizarre, he sat there for a while then just went for it and made a quick exit."

Amy Griffin, an art restorer at London's Simon Gillespie Studio, said she was optimistic that the painting could be repaired.

"The exact material the graffiti was done in will determine how quickly it can be removed," she said. "If it is water soluble this may be done quickly but if it has stained the original paint the conservation may take longer and some retouching might be needed."

Griffin said that while the painting wasn't on the market, the value would only be affected if the new black paint couldn't be removed.

"Removing graffiti or accidental damage to paintings done with pens, paint or even old restoration is a daily part of a conservator's job and the Tate conservation department is one of the best in the world," she said.

The damaged painting is part of Rothko's Seagram series. Originally commissioned for the Four Seasons' restaurant in New York, the artist changed his mind about the project and gave the works to galleries, including Tate Modern.

Much of Rothko's work is characterized by canvases with large rectangular blocks of color.

The last major piece by the artist to be sold was his "Orange, Red, Yellow". It  fetched $87 million at an auction in New York earlier this year.

The Tate Modern is no stranger to action by so-called artists. In 2000, two Chinese performance artists tried to relieve themselves in one of the gallery's most famous sculptures: a urinal by Marcel Duchamp.

The Metropolitan Police confirmed to NBC News that they were investigating the incident but said Monday that no arrests had been made.

Reuters contributed to this report.

More world stories from NBC News:

• Debt-choked Greece aims to sell off islands, marinas, more
• Abu Hamza, 4 others tied to al-Qaida arrive in US
• New role for rescued bear cubs
• Americans travel to Pakistan to protest US drone strikes
• Court: Kenyans tortured by colonial regime can sue UK
• Tourists fined as Rome declares 'War on the Sandwich'
• Stay informed: Sign up for our newsletter

Follow World News from NBCNews.com on Twitter and Facebook

 

Updated at 6:45 p.m. ET: LONDON - Elton John sang "I'm Still Standing," Stevie Wonder crooned "Isn't She Lovely," and Paul McCartney sent "All My Loving" as musical royalty celebrated Queen Elizabeth II's 60-year reign with a concert outside Buckingham Palace on Monday. But the joy was tempered by news that the queen's husband, Prince Philip, had been hospitalized with a bladder infection.

About 12,000 contest winners watched the live performances as part of four days of nationwide celebrations for the Diamond Jubilee marking the queen's 60 years on the throne. Members of the royal family, including Charles, his wife Camilla, Duchess of Cornwall, and Princes William and Harry sat in a royal box to watch the show. The queen wore a gold lame cocktail dress under a dark cape. 

Monday’s concert also featured Ska band Madness singing 1980s hit "Our House" from the roof of the 775-room palace. The band changed the lyrics to use proper English: "Our house, in the middle of one's street."

It's official: Twitter kills the Queen's English

---

The veteran entertainers seemed most popular. The crowd roared along to Cliff Richard's, "Congratulations," and cheered Bassey singing — fittingly — "Diamonds are Forever." Prince Harry could be seen singing along — "Why, why why?" — as Tom Jones belted out "Delilah," while Prince William and his wife Kate joined in on John's "Crocodile Rock."

McCartney closed the concert playing "Ob-La-Di, Ob-La-Da" on a Union Jack guitar before the queen took the stage with her family.

Palace officials said the prince, who will turn 91 on Saturday, was taken to the King Edward VII Hospital in London from Windsor Castle on Monday as a precaution and will remain under observation for a few days.

As the Diamond Jubilee show ended, Prince Charles took the stage and encouraged concertgoers to make some noise for his father. The crowd responded with a roar and chants of "Philip."

The heir to the throne paid tribute to his mother, addressing her as "Your Majesty — Mummy" and leading the crowd in three cheers for the monarch.

Did the queen enjoy the music? Her musical tastes are a mystery, and she appeared to be wearing yellow ear plugs as she observed the concert, according to The Associated Press. According to The Guardian newspaper, the only song the queen has ever been known to request is "Some Enchanted Evening" from the Rodgers and Hammerstein musical "South Pacific."

Despite the dreary weather, organizers said more than one million people gathered on the banks of the Thames to watch the 86-year-old monarch glide past in a barge decorated with flowers, with her closest family at her side.

In the flotilla were kayaks, rowboats, barges and the Motor Torpedo Boat 102 on which the Allied Forces commander, Gen. Dwight Eisenhower, and British Prime Minister Winston Churchill inspected warships before the 1944 D-Day invasion of Nazi-occupied France. 

A gloomy, gray - and great - day for the UK

All were decorated with flags and banners, making a colorful spectacle harking back to Tudor times when river pageants regularly took place for royal festivities.

Six participants in the pageant were treated in hospitals for exposure to the cold and wet, and medics attended to about 40 spectators along the river.

After the concert, a network of 4,000 beacons were lit across the United Kingdom and Commonwealth, leading into Tuesday, the final day of the extended holiday weekend.

The small Pacific island nation of Tonga claimed the honor of lighting the first beacons. Another was scheduled to be lit in Kenya at the Treetops Hotel, where Elizabeth was informed of her father's death in 1952, making her the queen.

The jubilee celebrations will conclude on Tuesday with a thanksgiving service at St Paul's Cathedral, a carriage procession along the Mall avenue, a fly past and farewell wave from the royal family to crowds gathered in front of Buckingham Palace – events that will be covered live on a special edition of NBC’s TODAY.

Secret donors, foreign firms bankroll UK’s Diamond Jubilee celebration

The jubilee event have underlined broad support for the queen in Britain, where she is riding high in opinion polls and is seen as a symbol of service, stability and national unity.

The displays of pomp and pageantry also gave a lift to many at a time of economic austerity and spending cuts, and boosted confidence ahead of the summer Olympic Games.

Support for the royal family is not universal however, with views ranging from indifference - around two million Britons traveled abroad to benefit from the extra days off - to outright opposition.

Queen's critics face uphill battle during jubilee

"Her achievement is just staying alive, doing little and saying less," Graham Smith, head of campaign group Republic, told Reuters on Sunday.

His group estimates that the royal family, which officially sets taxpayers back between 30 and 40 million pounds a year, in fact costs closer to 200 million pounds when security and travel are included.

Queen Elizabeth is only the second monarch to mark 60 years on the throne, after her great-great-grandmother Queen Victoria reached the milestone in 1897. She is also on course to become the longest-serving British sovereign in 2015.

NBC News, msnbc.com's Alastair Jamieson, The Associated Press and Reuters contributed to this report.

More world news from msnbc.com and NBC News:

• Will Saudi-Bahrain union plan provoke Iran?
• US drone strikes in Pakistan kill 27 people in 3 days
• New Vatican documents leaked after arrest of pope's butler
• Jublilee flotilla: A gloomy, gray - and great - day for UK
• Murderer's corpse dragged from car, eaten by bear in Canada
• Queen's critics face uphill battle during Diamond Jubilee
• Tahrir Square occupied as anger grows over Mubarak verdict
• Google tells Chinese when they're being censored
• Secret donors, foreign firms bankroll UK queen's celebration

Follow us on Twitter: @msnbc_world

Story updated 1:15 p.m. ET: The local authority, Camden Council, said it was confident Reid "had made an error in good faith" when he appointed his wife, but said the matter was being investigated by Britain's Office for Judicial Complaints.

Story published 11:30 a.m. ET: The coroner who oversaw the inquest into the death of singer Amy Winehouse has resigned after her qualifications were questioned, officials in Britain said on Wednesday.

Suzanne Greenaway ruled in October that the 27-year-old soul singer had died from accidental alcohol poisoning.

---

However, she resigned after authorities learned she had not been a registered U.K. lawyer for five years as required. It means the verdict in Winehouse's case and 11 others carried out by Greenaway could be subject to a High Court challenge.

Winehouse's relatives said they were still absorbing the implications of the news.

Greenaway had been appointed an assistant deputy coroner in London by her husband, Coroner Andrew Reid. She had practiced law for a decade in her native Australia.

Reid said Wednesday he was "confident that all of the inquests handled were done so correctly" — but offered to hold inquests over again if the families of the deceased wanted it. Greenaway had been in the job since 2009.

Winehouse's family said it had not yet decided what to do.

In a statement, the family said it was "taking advice on the implications of this and will decide if any further discussion with the authorities is needed."

The Sun newspaper, which broke the story, said the dozens of verdicts given by Greenaway would only be overturned if they were challenged in Britain's High Court.

A security guard found Winehouse dead in bed on July 23 at her home in the Camden district of north London. The singer, known for her distinctive beehive hairdos and multiple Grammy-winning album "Back to Black," had battled drug and alcohol addiction for years.

The inquest heard evidence from a pathologist, Winehouse's doctor, the security guard who found her and a detective who described seeing three empty vodka bottles in her bedroom. It appears unlikely that a second inquest would produce a different conclusion about how she died. 
 
The full statement issued by Reid on Wednesday was reported in north London newspaper, the Camden New Journal. It read: "I appointed my wife as an assistant deputy coroner as I believed at the time that her experience as a solicitor and barrister in Australia satisfied the requirements of the post. In November of last year it became apparent that I had made an error in the appointment process and I accepted her resignation.

"While I am confident that all of the inquests handled were done so correctly, I apologise if this matter causes distress to the families and friends of the deceased. I will be writing to the families affected to personally apologise and offer for their cases to reheard if requested."

Although the singer was adored by fans worldwide for her unique voice and style, praise for her singing was often eclipsed by lurid headlines about her destructive relationships and erratic behavior. Winehouse herself turned to her tumultuous life and personal demons for material, resulting in hit songs such as "Rehab" and "Love Is a Losing Game."

Msnbc.com's Alastair Jamieson in London and The Associated Press contributed to this report.