The Turkish prime minister urged separatist Kurdish rebels on Friday to surrender to security forces and benefit from an existing amnesty for those who voluntarily leave the guerrilla group. Turkey has massed thousands troops on its rugged border with Iraq for a possible cross-border offensives against the rebels, who have been launching attacks from bases in northern Iraq. Turkish troops are also fighting rebels inside Turkey in areas near the border. Turkish army helicopters in recent weeks have dropped thousands of leaflets on mountain paths used by the rebels of the Kurdish Workers' Party, or PKK, to infiltrate Turkey. The leaflets tell of the amnesty and urge rebels to leave the PKK.