The peace group's 34 members, including eight Kurdistan Workers' Party (PKK) rebels, were taken in for questioning as soon as they walked through the Habur gate on the border between Iraq and Turkey.

Four prosecutors sent to the border area to meet the group were to determine whether those held had committed any crimes and should be taken into custody.

More than 40 lawyers travelled to Habur to assist the group during questioning at military barracks inside the border area, one of the attorneys told Anatolia news agency.

Turkish officials have said the group's members were welcome if they were in Turkey to turn themselves in, but senior PKK commander Murat Karayilan told the pro-Kurdish Firat agency on Sunday that the group's aim was not surrender.

Rallies in support of the group were held in several cities. Some 5,000 people gathered in a central square in Diyarbakir, the biggest city in the mainly Kurdish southeast, answering a call by the Kurdish Democratic Society Party.

"Welcome peace ambassadors! Hand in hand for an honourable peace," chanted the protestors, along with slogans in favour of Abdullah Ocalan, the jailed leader of the rebel PKK.

Similer demonstrations took place in Batman and Mardin in the southeast and the eastern cities of Tunceli, Van and Mus, as well as Izmir in the west and the country's biggest city Istanbul, both of which have sizeable Kurdish communities.

A large crowd -- around 2,500 people, according to police -- marched down Istiklal Avenue, the main commercial street in Istanbul's European quarter, behind a banner which read "Open the Way for Peace".

"The ambassador of peace is in Imrali," the protestors shouted, in reference to the prison island where Ocalan has been held since his capture in 1999.

"Bravo PKK, the people are here," they said, flashing the V-sign for victory.

The PKK announced last week it would send "peace groups" from Iraq, where the rebels have rear bases, and Europe, on a proposal from Ocalan, to help advance Ankara's bid for peace.

The Firat news agency on Monday published pictures of the rebels, dressed in green combat fatigues and carrying no arms, leaving their camp for Turkey.

The group had brought with them a list of demands to hand over to Turkish authorities, Firat said.

The demands included an end to Turkish military operations against the PKK, negotiations for a solution, a constitutional recognition of the Kurdish identity and greater language and cultural rights for the country's 12 million-strong Kurdish community.

Since August, the government has been trying to build public support for an iniatitive to grant Kurds greater rights and try to erode support for the PKK, which has been fighting for self-rule in the southeast since 1984.

Ankara however rejects dialogue with a group that it has outlawed as a terrorist organization and has vowed to pursue military action against them.

More than 45,000 people have been killed in the conflict, which also displaced thousands and led to allegations of gross human rights violations.

The PKK had sent two groups of militants in 1999 on a similar peace initiative, but they were arrested and then jailed for belonging to the PKK.