The Bush administration cautioned Turkey (search) against pursuing Kurdish militants across the border into Iraq, saying it would be a difficult operation that could have "unintended consequences."

Assistant Secretary of State Daniel Fried said Monday the PKK militants posed a challenge to Turkey, and he condemned attacks on "our friend and NATO partner."

But while Turkey defends its border with Iraq and works with the United States to counter terror, "cross-border military action" would be a mistake, Fried said.

He suggested efforts to promote a unified and democratic Iraq could be damaged, but otherwise did not elaborate on his warning.

Turkey has felt the sting of terror attacks. On Saturday, a bomb destroyed a minibus in an Aegean beach resort, killing five people.

A top commander of the Kurdistan Workers' Party (search), or PKK, Zubeyir Aydar, condemned the attack in a statement Saturday while the PKK's military wing said it had nothing to do with the bombing.

But the Kurdistan Freedom Falcons Organization (search), a hardline group believed to be linked to the PKK, claimed responsibility for a bombing attack in the nearby resort of Cesme that wounded 21 people.

Fried's remarks were made in response to questions after he delivered a speech on U.S. relations with Turkey to the Washington Institute of Near East Policy, a private research group.

The speech was prepared by Undersecretary of State Nicholas Burns, who was diverted to deal with the visit of Indian Prime Minister Manmohan Singh.

In the speech, the Bush administration praised Turkey as both a U.S. partner and "very much a part of Europe." The speech counseled Turkey to be patient in seeking membership in the European Union but made clear Turkey had U.S. support.

"Our common values and interests draw us together," Fried said in Burns' behalf.

But on dealing with the outlawed PKK, Fried questioned any decision by Turkey to send troops into Iraq in pursuit.

Prime Minister Recep Tayyip Erdogan said last week Turkey reserved that right but had no immediate plans to take such action.

Both the United States and the European Union classify the PKK as a terrorist organization.

Turks worry the war in Iraq could lead to Iraq's disintegration and creation of a Kurdish state in the northern areas. That could embolden Kurds in southeastern Turkey, where the Turkish army has been battling Kurdish rebels since 1984. The fight has left 37,000 dead.

"We share the view that the PKK is a terrorist organization," Fried said. "There is no place in Iraq for the PKK."

"It is our problem, too," the State Department official said.