Polish police detained on Friday Chechen separatist leader Akhmed Zakayev, a World Chechen Congress spokesman said.
The spokesman said Zakayev was detained in Warsaw while on his way to the Polish prosecutor's office to present materials relating to a Russian extradition request for him on terrorist charges.
Russia placed Zakayev on the international wanted list in 2001.
“Poland is a free country - I have nothing to fear,” he told journalists when he later arrived at the prosecutor’s office.
Zakayev is in Warsaw to take part in the World Congress of Chechen People.
In 2002, British authorities granted political asylum to Zakayev and he currently lives in London.
Russia has repeatedly asked Britain to extradite him, but the request has invariably been refused.
Zakayev, who took part in the first Chechen War and led attacks on federal forces, denied in 2009 claims by Russia's security services that he was "attempting to revive the militant movement" in the region.
He also said he was ready for talks with Chechen head Ramzan Kadyrov, who subsequently said he would welcome Zakayev's return to Chechnya.
Zakayev, who has spoken out against Islamic radicalism in the North Caucasus, was “sentenced to death” by Chechnya's most wanted militant leader, Doku Umarov, in 2007.
"He practices a democratic religion, calls for secularism and prefers laws established by people to the law of Allah," the statement said.
MOSCOW/WARSAW, September 17 (RIA Novosti)