Aussie tourist injured in Greek arrest crossfire

An Australian man has been caught in the crossfire as Greek police captured far-left extremist Nikos Maziotis - one of the country's top fugitives - after a shootout in central Athens.

"Nikos Maziotis has been arrested," a police source said on Wednesday, adding that a police officer had been injured in the shooting near the tourist district of Monastiraki.

According to early reports, two male tourists - an Australian and a German - were also lightly hurt in the exchange of fire, the police source said.

Maziotis himself, a leading member of defunct militant outfit Revolutionary Struggle, was more seriously injured, state television Nerit reported.

"I saw a man being taken away with his hands behind his back, he was bleeding profusely," a witness told reporters at the scene.

"I believe he was wearing a wig," she added.

Media reports said Maziotis was armed with a handgun and a grenade, which he threw at the police but failed to explode.

Maziotis, 42, and his companion Panagiota Roupa - also a one-time member of Revolutionary Struggle - had been conditionally released from prison in 2012 and subsequently disappeared.

They have a four-year-old son who was born in an Athens hospital a few months after his parents were imprisoned in 2010.

Revolutionary Struggle, which first emerged in 2003, was once deemed by authorities to be the country's most dangerous far-left organisation and is on EU and US lists of terrorist groups.

The United States put a bounty on the group after it fired a rocket at the US embassy in Athens in 2007 without injuring anyone.