Austrian climate activists threw a black sticky substance on a priceless Gustav Klimt painting at a Vienna museum on Tuesday.

Activists from the “Last Generation” group poured "black, oily liquid" on Klimt’s 1915 “Death and Life” at the Leopold Museum before they could be apprehended by security.

A third activists attempted to glue himself to a protective barrier in front of the painting.

The group was protesting the use of fossil fuels by the Austrian government, it said.

The painting was not damaged due to being protected by a glass case.

According to reports of the incident, one of the activists shouted, “We have known about the problem for 50 years. We must finally act, otherwise the planet will be broken” and “Stop fossil fuel destruction."

After throwing the liquid on the painting, one of the protesters was pushed out of the way by a museum guard. The other protester glued his hand to the frame of the painting.

The group defended their actions in a tweet, insisting they were protesting against natural gas and oil which they claimed was a “death sentence to society.”

Museum officials told a press conference that the painting was not harmed in the attack and that they had increased security after the incident, Reuters reported.

"Fortunately the work of art was not damaged. Nonetheless, we are shocked that the Leopold Museum was in focus here," museum director Hans-Peter Wipplinger said.

He added that the group would be sent a bill for cleaning up the painting, estimated to be at least five figures in euros.

In October, Climate protesters defaced a Van Gogh painting of sunflowers at London’s National Gallery by throwing cans of tomato soup at it, BBC News reported.

According to the gallery, the painting was under glass and not damaged. The Metropolitan Police arrested two people behind the attack.