Ahead of the high-stakes talks, Erdogan warned Tuesday that he wants Bush to take "concrete, urgent steps" against the Iraq-based Kurdistan Workers' Party (PKK) and that US-Turkey ties will hinge on Washington's response.

White House spokeswoman Dana Perino cited "joint efforts to counter the PKK" but declined to spell out the US contribution against the group, which Washington and Europe both consider a terrorist organization.

"We have a joint desire, a joint need to make sure that the PKK is eradicated," she said.

Washington has pressed Ankara not to launch a large-scale incursion into relatively stable Kurdish northern Iraq, while Baghdad has warned that any such action would have "disastrous" results.

Bush will talk to Erdogan "about exercising restraint, limiting the actions against the PKK" as well as "making sure that they continue to have that dialogue with the Iraqis, because ultimately the neighbors need to work together to make sure that they solve this problem," said Perino.

In Ankara, Erdogan said that the PKK's safe have in northern Iraq would dominated the upcoming talks, calling it a "sincerity test" for all of the parties involved and a decisive force for shaping US-Turkish relations.

"I will openly tell him that we expect concrete, urgent steps against the terrorists," Erdogan said in a speech in parliament to deputies of his Justice and Development Party.

"Our talks (with Bush) will make them better understand that Turkey's patience has run out and that we are determined to unhesitatingly take all the steps to finish off terrorism."

Erdogan also said he would seek an explanation from Washington on how US military hardware given to Iraqi forces had ended up in PKK hands.

He said he would discuss "the groups on which the terrorist organization relies" -- an apparent reference to the Iraqi Kurds, who run northern Iraq and whom Ankara accuses of tolerating and even supporting the PKK.

Breaking the drug-trafficking rings the PKK uses for financing would also be on the agenda, he said, adding that he would ask the US to put forward a roadmap on the procedures it intended to take.

Turkey still considered diplomacy its favored route to resolve the problem, but the threat of military action remained, Erdogan said.

Last week, Perino acknowledged that Turkey was "skeptical" after Iraqi Prime Minister Nuri al-Maliki vowed to crack down on the PKK and shut its offices -- almost the exact same actions he promised in September 2006.

The Turkish parliament earlier this month authorized military action in northern Iraq to strike at the PKK, which has waged a bloody campaign for Kurdish self-rule in southeast Turkey since 1984.

Washington strongly opposes a Turkish incursion, but is in an awkward position between two key allies -- NATO-member Turkey and the Iraqi Kurds, who run northern Iraq but are reluctant to confront fellow Kurds of the PKK.