VILNIUS -- Late Russian opposition leader Alexei Navalny's long-time aide Leonid Volkov was assaulted with a hammer in the Lithuanian capitol Vilnius on Tuesday, former Navalny spokesperson Kira Yarmysh said.

"Volkov has just been attacked outside his house. Someone broke a car window and sprayed tear gas in his eyes, after which the attacker started hitting Leonid with a hammer," she wrote on social media website X.

She posted images showing Volkov with a bruise on his forehead, blood coming from a leg wound, and a vehicle with damage to the driver's door and window.

Lithuania's Foreign Affairs Minister Gabrielius Landsbergis, who also leads Homeland Union, the ruling party, called the assault "shocking."

"Perpetrators will have to answer for their crime," he wrote on X.

Lithuanian police said they had been informed a man was beaten outside his home, and were investigating.

Police fenced off a pine forest near Volkov's house on Vilnius' northern outskirts, and officers with dogs and flashlights were seen searching it late on Tuesday night.

A large part of Navalny's political group, the Anti-Corruption Foundation, which includes Volkov, are residing in European Union and NATO member Lithuania after fleeing Russia.  

Reporting by Andrius Sytas in Vilnius; Editing by Stephen Coates