The United States needs to step up efforts to prevent Kurdish separatists from operating cross-border attacks on Turkey from Iraq, US and Turkish officials said.

President George W. Bush sought on Wednesday to rally support for the war in Iraq, appealing to Americans on Independence Day for “more patience, more courage and more sacrifice”.

The US tactic of using armed Sunni tribesmen in the fight against Al Qaeda in Iraq offers short-term gains to weaken the insurgency, but could set the stage for a full-scale sectarian civil war when the Americans begin to draw down their forces.