The man, identified as Cevat Soysal, has been flown to Turkey. Reports said he was arrested in the former Soviet republic of Moldova.

His capture comes five months after the PKK's leader Abdullah Ocalan, now facing the death sentence, was seized in Kenya.

Turkey's national intelligence agency said Mr Soysal intensively engaged in training PKK militants and organising pro-PKK activities in Europe and Middle East.

But the rebel Kurdistan Workers Party (PKK) played down Mr Soysal's importance and insisted he was not seized but handed over to the Turkish authorities by Moldova.

It denied he ranked as a senior figure.

A photograph released by Turkey's MIT intelligence service showed a hooded man being helped down the steps of a small private aircraft.

The BBC's Tom Kankkonen: "The Turkish forces are trying to stamp out the PKK"

Turkish Prime Minister Bulent Ecevit said the arrest followed "a very successful operation'', but refused to identify the country where he was captured.

However a statement released by the PKK said: ''Our comrade Cevat Soysal was handed over to the Turkish state after being arrested by Moldova, not as a result of any secret operation by Turkey."

Political asylum

The leader of the tiny Kurdish community in Moldova, Hamghin Abdullah, said Mr Soysal was seized on 13 July when he left a residence to make a telephone call to Germany where he lives.

The reports come as the German Foreign Minister, Joschka Fischer, is about to begin a visit to Ankara.

Germany, where Mr Soysal has political asylum, denied playing any role in the arrest.

Romanian role

The arrest of Ocalan, earlier this year prompted a wave of protests by Kurdish sympathisers across Europe and bomb attacks in Turkey.

Ocalan, who has led a 14-year armed campaign for a separate Kurdish homeland, was sentenced to death by a Turkish court last month.

The Turkish intelligence agency said Mr Soysal became more active in training PKK militants and organising pro-PKK activities in Europe after Ocalan was apprehended.

In an interrogation earlier this year, Ocalan said Mr Soysal was in charge of training rebels abroad, especially in Romania.