The returnees were among the 34 people, including four children, who crossed from Iraq in October in a show of support for a government plan to expand Kurdish freedoms in a bid to end a 26-year separatist campaign by the outlawed Kurdistan Workers' Party (PKK).

Although they self-styled "peace envoys" were initially set free, the 30 adults -- eight PKK militants and 22 Kurdish sympathizers -- were charged in April with links with the PKK, risking jail terms of up to 20 years.

Ten of the defendants were jailed pending trial in the first hearing of the trial in June.

It was not immediately clear how many of the group crossed the border back to Iraq. The NTV news channel put their number at 19 while the CNN-Turk news channel gave their figure as 14.

The Firat news agency, which is close to the PKK, quoted a spokeswomen for the returnees as saying on their return to Iraq that the judicial onslaught had made it impossible to pursue peace efforts.

"We extended the hand of peace and found only air," the spokeswoman was quoted by the agency on its website.

Queried by journalists over the activists' return, Turkish Justice Minister Sadullah Ergin said he had no concerete information confirming that they had gone back to Iraq.

"We have received news reports to that effect, I wish they had stayed in this country to contribute to" the government's efforts for peace, he said.

Last year, the government said it was initiating a two-pronged strategy of improving Kurdish rights while keeping the PKK under military pressure to end its deadly campaign for self-rule.

The initiative however has been delivered a heavy blow by increasing PKK violence since May when jailed Kurdish rebel leader Abdullah Ocalan said he was abandoning efforts for peace with Ankara.

Some 45,000 people have been killed since 1984 when the PKK, blacklisted as a terrorist group by Turkey and much of the international community, took up arms for self-rule in Turkey's mainly Kurdish southeast.