The report says that Netrebko, who has dual Russian-Austrian citizenship, donated a check for 1 million rubles (€14,860 or more than $18,000) to Oleg Tsaryov, the self-proclaimed leader of the 'South-east movement', based in the breakaway Donetsk People's Republic.

Tsaryov is on a list of persons sanctioned by the EU for their role in events in east Ukraine, and calls himself the chairman of the parliament of Novorossia.

Netrebko claimed on Monday that her donation was solely for cultural reasons, to support performing artists in the Russian-backed enclave.  She was also photographed draped in the flag of Novorossia while attending a joint press conference in St. Petersburg, a move which Austria's foreign ministry has described as 'problematic.'

“Donetsk has not surrendered, just like Leningrad did not surrender [during the Nazi siege],” Tsaryov said. “This [donation] is important for us not just because it’s money, but because it is support for us”, reported The Guardian newspaper on Monday.

Netrebko said she would visit Donetsk and sing at the opera theatre as soon as military hostilities in the region were over. Asked about her views on the conflict, she insisted she was apolitical. “This is politics and I have nothing to do with politics, I just want to support art,” she said.

“I have a lot of musician friends in Donetsk, we have been writing to each other a lot, and they told me the theatre was sacred for them, and the building had been partly damaged. I decided that I wanted to help as much as I can. I think it’s the right thing to do because art is art, and helps us get through all situations,” Netrebko said.

Dumped by Austrian airlines

The Austrian government warned on Tuesday that photos of the event "will be immediately used for propaganda purposes."

Austrian airlines, which for a long time used Netrebko in its advertising, has dumped the singer due to her views.  

"Anna Netrebko used to be an advertising partner of Austrian Airlines, the advertising contract with Ms Netrebko expired at the end of November," a spokesman told RFE/RL. "We clearly distance ourselves from any extreme political position and the use of armed violence."

According Netrebko's website, on December 9, 2014, Austrian Airlines was scheduled to launch a new advertising campaign, featuring Netrebko and Austrian Olympic gold medal-winning downhill skier Matthias Mayer. The campaign would have run in Austria, Germany, Italy, and Switzerland. 

Boycott campaign launched

A new campaign has launched on Twitter to boycott the Russian singer, with thousands of people tweeting their anger over her collaboration with the people who were allegedly responsible for the shooting down of a Malaysian airlines plane in July.

The campaign uses the hash tag #BoycottAnnaNetrebko, and is actively trending on Twitter.