WASHINGTON — President Bush today pledged fresh help to Prime Minister Erdogan of Turkey in fighting Kurdish rebels, declaring them “an enemy of Turkey, a free Iraq and the United States.”

In an Oval Office session, Mr. Bush offered intelligence sharing to help combat the Kurdistan Workers’ Party, or PKK. Mr. Bush also said top military figures from America and Turkey would be in more regular contact in an effort to track the movement of the guerrilla fighters.

“I made it very clear to the prime minister that we want to work in a close way to deal with this problem,” Mr. Bush told reporters.

With Turkish troops massed on the border of his country, Mr. Erdogan is weighing a major cross-border attack against PKK rebels in northern Iraq. The guerrillas have killed more than 40 Turks in the past month in cross-border raids, and pressure is growing on Mr. Erdogan to hit back.

The White House worries that a Turkish incursion into Iraq could bring instability to what has been the calmest part of Iraq and could set a precedent for other countries, such as Iran, that have conflicts with Kurdish rebels.

Yet, when asked about the possibility of Turkey attacking Iraq, Mr. Bush dismissed the question as hypothetical.

He tried instead to assure Turkey that America is providing support.

“It’s fine to speculate about what may or may not happen,” Mr. Bush said. “But nothing can happen until you get good intelligence. We need to know where people are hiding, and we need to know what they’re doing.”

Mr. Erdogan said his government has the authority to mount an incursion into Iraq if necessary. But he gave no further indication of his intentions.

Instead, like Mr. Bush, he emphasized cooperation with America.

“As strategic partners, we are fighting jointly against international terrorism in the world,” Mr. Erdogan said.

It is widely thought that the bulk of the PKK forces — which traditionally halt operations in the winter because of supply and logistical difficulties — had scattered as far as southern Iraq, as well as melting into the populations of large cities in the north.

Mr. Erdogan said in advance of meeting Mr. Bush that he was expecting the talks here to result in “solid steps” from America. Their meeting came a day after the PKK released eight soldiers it had been holding for two weeks since their capture in an ambush inside Turkey along the Iraqi border.

Mr. Bush noted that Mr. Erdogan’s government had consulted America about getting the soldiers released.

“There is at least one effective measure for people in Turkey to see, that when we work together, we can accomplish important objectives,” Mr. Bush said.

An American ambassador to Turkey in the Clinton administration, Mark Parris, and now a visiting fellow at the Brookings Institution, said that today’s meeting would be the last chance for the Bush administration to repair strained relations with Ankara.

“If Erdogan hears something relatively reasonable and concrete, you can put this relationship back together,” Mr. Parris said. “If not, that effort might have to wait for a new administration.”

For weeks, the Bush administration has stressed the need for a diplomatic solution between Turkey and Iraq.

During a trip to Turkey last week, Secretary of State Rice promised to redouble efforts against the PKK. But her Turkish counterpart, Foreign Minister Ali Babacan, made clear his government was not satisfied.

Following a meeting in Istanbul with Iraqi officials including Prime Minister al-Maliki during a conference on Iraq, Ms. Rice won a pledge that Iraq would step up efforts to fight PKK terrorism. Later Saturday, Iraqi Kurd authorities shut down the Irbil and Sulaimaniyah offices of the Kurdistan Democratic Solution party, an organization that allegedly had close ties to Kurdish guerrillas.

But Turkey was still looking for more from America.

“I am expecting that this trip will result with the United States … taking solid steps,” Mr. Erdogan said Saturday prior to leaving Turkey for Washington.

The intensity of Turkey’s demands on the PKK has risen as hit-and-run raids by the rebels and other fighting have left dozens of soldiers and civilians dead in recent month. The skirmishes were the latest in a conflict that has seen nearly 40,000 people killed.