Mr Ocalan, who is wanted by Ankara on charges of terrorism and murder, has not been seen since leaving Italy two weeks ago.

He is thought to have been shuttling around Europe in a private plane in search of sanctuary.

Turkish Prime Minister Bulent Ecevit has suggested that Mr Ocalan may have been heading for Belarus, where he would in effect be under Russian protection.

Speaking on television on Tuesday night, Mr Ecevit said that such a move would allow Moscow to insist that Mr Ocalan was not on Russian soil, but the net result would be almost the same.

BBC Ankara Correspondent Chris Morris says the prime minister's previous comments on Mr Ocalan's odyssey have not always proved correct, but the PKK leader does have numerous supporters in Russia.

Search for safety

Middle East expert David McDowall: Many European countries are embarrassed

Various reports have said Mr Ocalan has landed or tried to land in Holland, Switzerland, Greece, Italy and Serbia since Monday morning.

Turkey's mass circulation Hurriyet ran the headline: "Like a Ping Pong Ball."

The hunt started when he reportedly tried to land at Rotterdam airport, where about 200 Kurds had gathered to greet him.

Turkey says he then flew briefly to Athens, but this has been hotly denied by Greece.

"Ocalan is not in Greece; he never was and never will be," said Greek Ambassador Dimitris Nezeritis.

On Tuesday, Ankara reportedly warned Yugoslavia, Switzerland and Norway against providing refuge for the rebel leader - their number one enemy.

US backing

The United States has backed Turkey's call for political leaders to return Mr Ocalan for trial.

Mr Ocalan was arrested in Italy in November after arriving on a flight from Moscow, following his expulsion from Syria.

Rome refused to extradite him on the grounds that a Turkish court could sentence him to death. The affair has sparked a fierce diplomatic row between the two countries.