European police said Thursday they had busted a criminal gang suspected of snatching at least 170 rare books written by Russian literary greats such as Alexander Pushkin or Nikolai Gogol.

The suspected thieves posed as researchers at libraries, distracting staff while an accomplice replaced the valuable first editions with a copy of "outstanding quality", Europol said.

"In other cases, members simply broke into libraries and took books they had already seen earlier," said prosecutors in Lithuania.

The books "of high historical and cultural value" were stolen in seven different European countries and worth around 2.5 million euros ($2.4 million), authorities said.

Police arrested four Georgian citizens and raided 27 locations in Georgia and Latvia. One book was recovered and many others seized that are now being examined.

Leading up to the raids, three suspects had been arrested in Estonia, France and Lithuania, with another two suspects under judicial supervision in France, said Europol.

Prosecutors in Georgia said the suspects had been charged with offences that could result in a sentence of between six and 10 years in prison.

Poland and Baltic states said last year that 19th century Russian literature tomes were disappearing, with originals replaced by fakes and some resurfacing later in Russia.