Hopes of a peaceful end to the showdown between Turkish troops and Kurdish rebels seemed remote today, despite the offer of a ceasefire.
Iraq announced that the PKK dissidents who have camps in the north of the country had unilaterally declared an end to the violence.
The announcement came a day after they killed 12 Turkish soldiers and abducted another eight in an ambush on the Turkey-Iran border.
But Turkey has already rejected several previous similar ceasefires declared by the rebels, saying it would continue fighting until all surrendered or were killed.
Sources in the Turkish government said it was unlikely they would accept the new offer.
Meanwhile dozens of Turkish military vehicles loaded with soldiers and heavy weapons rumbled toward the Iraqi border today in the aftermath of yesterday's ambush.
As fears of an all-out war breaking out grew, Turkey's foreign minister promised his country will pursue diplomacy before it sends troops across the frontier.
The military said it had had no contact with the eight soldiers captured yesterday.
The ambush outraged an already frustrated Turkish public. Demonstrations erupted across the country and opposition leaders called for an immediate strike against rebel bases in Iraq, despite appeals for restraint from Iraq, the US and European leaders.
More than 2,000 protesters in Istanbul, mostly members of an opposition party, denounced the attack and urged the government of Prime Minister Recep Tayyip Erdogan to resign.
In the capital Ankara, hundreds convened at a main square shouting "Down with the PKK and USA!"
Ambulances decorated with Turkish flags drove around main streets, their sirens on.
Some 13,000 schoolchildren in Bilecik in eastern Turkey held a minute of silence while people marched down a main street, waving the Turkish flag.
In Bursa, in north-west Turkey, some protesters walked to a military conscription office and asked to enlist to fight rebels.
In Washington, the State Department said the US had opened an all-out diplomatic push to urge Turkey not to invade northern Iraq.
"In our view, there are better ways to deal with this issue," spokesman Sean McCormack said, stressing that the US regards the PKK as a terrorist organisation.
"We will continue these diplomatic efforts with all good intentions to solve this problem caused by a terrorist organisation," Turkish Foreign Minister Ali Babacan said.
"But in the end, if we do not reach any results, there are other means we might have to use."
The rebel attack came four days after the government said it was ready to deploy troops across the border in Iraq.