Ankara has long been frustrated by US and Iraqi reluctance to clamp down on bases of the separatist Kurdistan Workers' Party (PKK) in the mountains of northern Iraq, from where the rebels infiltrate neighboring Turkey to engage in anti-government violence.

"We now have a new, stronger government in Baghdad. We believe that this can provide a good basis to work more effectively together," Ambassador Ross Wilson said during a visit to Diyarbakir, the main city of the predominantly Kurdish southeast.

"We have already been discussing with Iraqi authorities our strong concerns about the PKK and the need for effective action to deal with its presence in northern Iraq," he said.

Wilson reiterated Washington's commitment to support Ankara's struggle against the group, blacklisted as a terrorist organization by Turkey, the European Union and the United States.

The issue has become of increasing importance for Ankara in recent months as clashes have escalated between the PKK and the army and a series of bomb attacks in urban centers has been blamed on the group.

Thousands of armed PKK militants have found refuge in northern Iraq since 1999, when the group declared a unilateral ceasefire after the capture of its leader, Abdullah Ocalan. The truce was called off in June 2004.

Turkey has massed troops along the border with Iraq to stop what it says is increasing infiltration by the rebels since the arrival of spring.

During a visit to Ankara last month, US Secretary of State Condoleezza Rice warned Ankara against cross-border operations and called for renewed trilateral meetings between Washington, Baghdad and Ankara to discuss measures against the PKK after the new Iraqi government took office.

The Kurdish conflict has claimed more than 37,000 lives since the PKK took up arms for Kurdish self-rule in the southeast in 1984.