Updated

President Abdullah Gul said Tuesday that Turkey will do "what it believes to be right" in the fight against Kurdish rebels in northern Iraq, as tens of thousands of troops sat poised on the southeastern border awaiting the order to attack.

But with winter rapidly approaching in the mountainous region, and intense pressure from the U.S. to avoid an all-out cross-border incursion, officials and experts said Turkey will most likely be looking toward a limited offensive involving raids and aerial assaults.

Several possibilities are currently being discussed, including F-16 strikes on rebel positions, helicopter raids and special forces missions, according to a government official familiar with the planning.

"The area is heavily mined and a big incursion with tens of thousands of troops is out of the question," he said, speaking on condition of anonymity because he was not authorized to speak to the press.

The U.S. and Iraq have been pressing Turkey to avoid a major cross-border attack on Kurdistan Workers' Party, or PKK, rebel bases in northern Iraq out of fear such an incursion would bring instability to what has been one of the calmest areas in Iraq.

In northern Iraq, a spokesman for one of the two parties that governs the semiautonomous region urged Turkey to refrain from any attack, but suggested scaled-down raids would not be as destabilizing.

"We reject any kind of Turkish military strike, whether limited or not," Azad Jindyany, spokesman for the Patriotic Union of Kurdistan, told AP in Sulaimaniyah. "A limited one would cause a limited problem, but an unlimited strike would destroy the whole situation."

A high-ranking retired military officer, who participated in the planning of previous incursions into northern Iraq in the mid-1990s, said Turkey was planning for airstrikes from planes and helicopter gunships, as well as special forces commando raids.

But scaled-down assaults wouldn't necessarily mean the use of large numbers of troops should be ruled out, he said.

"A few thousand troops could still penetrate the Iraqi border to block escape routes of the rebels during a pinpoint raid," he said, also on condition of anonymity because he was not authorized to talk.

PKK rebels have killed more than 40 Turks in hit-and-run attacks over the past month, mainly soldiers, raising the public pressure on Turkish Prime Minister Recep Tayyip Erdogan to retaliate.

Gul said Tuesday that Turkey had made its decision on what to do about the PKK rebels. While he did not specify what the decision was, he made clear that Turkey feels the PKK is leading to instability in the region itself.

"Iraq's stability cannot be limited to fighting terrorism in Baghdad or other regions," he said. "The terrorist organization in the north is also disrupting Iraq's stability."

Later, he added, "Turkey will carry out what its believes to be right with determination," state-run Anatolia news agency reported.

The comments came a day after U.S. President George W. Bush met in Washington with Erdogan and promised him that the United States would share military intelligence in the hunt for PKK rebels.

Following that meeting, Erdogan strongly suggested an attack was imminent.

With the Turkish government talking openly for weeks about the likelihood of an attack, both of the officials said intelligence information shows the PKK guerrillas have been evacuating their camps and melting away into cities and other regions.

In northern Iraq, Osman Ocalan, brother of imprisoned PKK leader Abdullah Ocalan, told AP that some fighters had moved toward Iran, and that there were now more PKK fighters there than in northern Iraq.

"PKK forces are split into three parts situated in Turkey, Iraq and Iran," he said. "If there is Turkish pressure on our forces in Iraq, the fighters will head toward Iran."

But an attack is still likely to go ahead, the Turkish government official told AP.

"The military, the government feel the pressure from the public to do something and there is need to satisfy that demand in some way," he said. "But most of them (the rebels) have left their camps and any attack would yield little concrete results other than satisfying Turkish public opinion and restoring Turkish-U.S. ties against a common enemy."

Bob Ayers, a former U.S. intelligence officer now with the London-based thinktank Chatham House, said he also expected any cross-border operation to be swift and that it would target PKK infrastructure. He added that it would stand to reason that the PKK fighters have started vacating border bases in light of the anticipated attack.

"It certainly would make sense," said Ayers, who had just returned from one of several trips to Turkey over the past year. "By dispersing, that provides them with a little security, because there's no way the PKK, given their limited numbers, could expect to engage the Turkish military and come out ahead."