Vienna: Climate activists on Tuesday poured a black liquid over Austrian painter Gustav Klimt's masterpiece "Death and Life" at Vienna's Leopold Museum, a spokesman told AFP.
"Restorers are working to determine whether the painting protected by glass has been damaged," said Klaus Pokorny.
A group of Austrian and German climate activists called "Last generation" claimed responsibility for the attack on Twitter.
In images shared by the group on social media two men can be seen pouring a black, oily liquid on the famous Klimt painting before being arrested by a museum employee.
"Stop fossil destruction. We're racing towards climate hell," one of the protesters shouted.
Admission to the Leopold Museum was free on Tuesday as part of a day sponsored by the Austrian oil and gas group OMV.
Numerous masterpieces across Europe have been attacked in recent weeks in protests at the lack of action against climate change.
They have glued themselves to a Francisco Goya in Madrid, thrown soup at Vincent van Goghs in London and Rome, and mashed potatoes on a Claude Monet.
In the wake of the protests, dozens of the world's top museums issued a joint declaration last week saying environmental activists who attack paintings "severely underestimate" the damage that could be caused.
The statement was spearheaded by the Prado in Madrid, and signed by the directors of more than 90 world-renowned museums including the Guggenheim in New York, Louvre in Paris and Uffizi in Florence.
