(CNN) -- A Chechen separatist leader was released from custody Friday evening, several hours after he was detained, state media reported.
A judge in Warsaw, Poland, denied a prosecutor's request to arrest separatist leader Akhmed Zakayev, who is in Poland for the World Chechen Congress, according to Russian state media agency Itar-Tass.
Akhmed Zakayev "is at large and may leave the country," court press secretary Wojciech Malek said, according to Itar-Tass.
A prosecutor could appeal the Polish court's decision to free Zakayev, Malek said.
After the ruling, Zakayev told reporters that he would travel to address the World Chechen Congress in Pultusk, about 60 km (40 miles) north of Warsaw, Russia's state-run RIA-Novosti reported.
"I do not intend to conduct an anti-Russian campaign. Poland has chosen to re-establish normal relations with Russia, its great neighbor, but we must also make sure that Russia also becomes a normal state," he said, according to RIA-Novosti.
Zakayev was a brigade general of the Chechen rebel forces during the 1995-1996 war and later served as culture minister, foreign minister and deputy prime minister in Chechnya's separatist government from 1996 to 1999.
After Russia crushed rebel rule during a second war with Chechnya that started in 1999, Zakayev emigrated to Europe, where he has been the head of the Chechen rebel government in exile.
Russia issued an international warrant for Zakayev's arrest in October 2001.
A year later, he was detained in Denmark but the Danish Justice Ministry rejected Russia's demand for Zakayev's extradition.
Then in December 2002, he moved to the United Kingdom, where another Russian extradition request was turned down. Political asylum was granted to Zakayev in November 2003 and he has been living in London ever since.
A Polish judge cited that decision in Friday's ruling.
"Beyond all doubt, a decision of one [European Union] member-country is valid for the whole of the European Union," Judge Petr Skhab said, according to Itar-Tass.
The Polish prosecutor's office had warned that Zakayev would be arrested on an international warrant if he arrived in Poland to attend the third World Congress of the Chechen People that was being held in the town of Pultusk through Saturday.
Russia previously said it would request Zakayev's extradition if he were apprehended.
"Due to the detention of Akhmed Zakayev in Poland and in accordance with the European convention on extradition, the Russian Prosecutor General's Office is currently preparing material with a Polish translation, which will be sent to the Polish authorities for (Zakayev's) extradition to Russia," the prosecutor's office said earlier Friday.
CNN's Maxim Tkachenko contributed to this report