Leonid Volkov said he suffered a broken arm and injuries from about 15 hammer blows to the leg in Tuesday night's attack, which occurred outside his home in Vilnius.

Earlier on Thursday the Kremlin declined to comment on the attack but said people should respect and listen to Russian President Vladimir Putin rather than be afraid of him, after Lithuania's president said "nobody is afraid (of Putin) here".

"It seems this is the work of Russia's special services," Darius Jauniskis, head of Lithuania's State Security Department, told reporters, without saying what the assessment was based on.

"We need to pay more attention to the security of the Russian opposition (based in Lithuania)," he added.

The agency previously said the attack was probably carried out to prevent the Russian opposition from influencing Russia's March 15-17 presidential election, in which Putin is expected to extend his 24-year rule by a further six years.

"We see that (Russian intelligence) is very seriously targeting this region and is undertaking action... We see (recruiting) activity in all three Baltic countries," Jauniskis said on Thursday.

Lithuania, which is a member of NATO and the European Union, has become a base for Russian and Belarusian opposition figures.

Volkov himself has blamed Putin for Tuesday's attack. Before the assault he had told Reuters that leaders of Navalny's movement in exile feared for their lives.

Navalny, Putin's most prominent critic, died last month in an Arctic prison. Russian authorities say he died of natural causes. His followers believe he was killed by the authorities, which the Kremlin denies.

Australian Associated Press