One of Russia’s most famous paintings was damaged on Friday in Moscow when an intoxicated visitor at Tretyakov Gallery grabbed a metal pole and dealt several blows to Ilya Repin’s 1885 canvas Ivan the Terrible and His Son Ivan.

He slashed the painting in three places and badly damaged the frame, according to Reuters. Fortunately, the faces and hands, which are among the painting’s most celebrated features, were not destroyed.

The attacker, identified as 37-year-old Igor Podporin, said he struck the painting because he felt “overwhelmed” after drinking more than two shots of vodka in the museum’s cafe.

However, some museum officials suggested he may have had a nationalist agenda. Curator Tatyana Gorodkova said in a press conference that she heard Podporin shout that Ivan the Terrible did not kill his son before he struck the painting—a belief held by some Russian nationalists.

“The incident was awful and frightening and speaks to the aggression which reigns in society,” said Tretyakov director Zelfira Tregulova. At a press conference on Monday, curators described the 19th-century masterpiece as Russia’s Mona Lisa and lamented some people’s refusal to distinguish between art and history.

In the aftermath of the destruction, Tregulova said the incident couldn’t have been prevented. “It was not possible to do anything. It was a question of seconds,” she told Reuters. Nevertheless the museum is reviewing its security practices and may ban the sale of alcohol on the premises. The painting will also be placed under bulletproof glass after its restoration.

Meanwhile, Russia’s deputy cultural minister Vladimir Aristarkhov called for harsher penalties for similar transgressions, which currently carry a three-year maximum sentence. He said a more effective deterrent is needed to make up for a shortage of security personnel in cash-strapped Russian museums.

This is actually the second time the painting has been harmed. In 1913, Repin was still alive to repair the painting after a knife attack, though the incident reportedly led the museum’s curator to take his own life.