SIRNAK, Turkey — Turkey's ruling party decided Tuesday to seek parliamentary approval for an offensive against Kurdish rebels based in northern Iraq, a move that could open a new front in the Iraq war and disrupt one of that nation's few relatively peaceful areas.

The government did not say it had decided to launch such an attack, which could jeopardize Turkey's ties with the United States. The U.S. warned against sending troops across the border and urged Turkey to work with Iraq's government to quell the Turkish Kurd guerrillas.

"If they have a problem, they need to work together to resolve it, and I'm not sure that unilateral incursions are the way to go," State Department spokesman Sean McCormack said. "We have counseled, both in public and private, for many, many months, the idea that it is important to work cooperatively to resolve this issue."

In the past, Turkish troops have made small-scale "hot pursuit" raids into Iraq that officials say do not require Parliament's approval. The last major incursion against the militant separatists operating out of Iraq's Kurdish region was in 1997.

There are widespread fears that a Turkish offensive would destabilize Iraq's Kurdish area, which has largely escaped the violence and political turmoil afflicting regions dominated by Shiite Muslims and Sunni Arabs.

Iraqi Kurds, who run a virtual mini-state in Iraq's north, have vowed to defend their borders. A spokesman for the Iraqi Kurdish regional government, Jamal Abdullah, urged Turkey on Tuesday to drop the idea of a military attack.

"We call upon the Turkish government to exercise self-restraint and not to turn the region into an unstable one," he said. "Such attacks will threaten the stability not only in Iraq but the whole region."

Turkey's decision to seek a parliamentary go-ahead was made during a three-hour meeting between Prime Minister Recep Tayyip Erdogan and officials from his governing Justice and Development Party, said a leading member of the party who was at the meeting.

The party wanted the measure to pass "as soon as possible" and would try to present it to Parliament on Wednesday, the lawmaker said in a telephone interview with The Associated Press. He insisted on anonymity because he was not authorized to speak to reporters.

Earlier Tuesday, the government said it had begun preparations for a military operation into Iraq in pursuit of the rebels after a series of deadly attacks on soldiers in recent days outraged Turks.

Turkey previously had said it would prefer that the United States and its Iraqi Kurd allies in northern Iraq crack down on the rebel Kurdistan Workers' Party, or PKK, which seeks to create an autonomous Kurdish state in Turkey's predominantly Kurdish southeast.

"Institutions concerned have been given the necessary orders and instructions to make all kinds of legal, economic and political preparations to end the presence of the terror organization in a neighboring country in the upcoming period, including if necessary a cross-border operation," said a statement issued after Erdogan met with security officials.

Over the last 10 days, more than two dozen soldiers and civilians died in attacks by PKK rebels in the southeast. The group, labeled terrorist by Washington and the European Union, has fought Turkish forces since 1984 in a war that has killed tens of thousands of rebels, soldiers and civilians.

The public mood made it likely Parliament would move quickly to approve an offensive.

It wasn't clear if Turkey's military planned to strike immediately after approval or wait to see if the action would prod the U.S. and its allies to take robust action against the PKK bases.

However, Turks already have debated a cross-border offensive through much of the year and any further delay could hurt the credibility of the tough-talking government. The military declared months ago that it was ready for an incursion into Iraq.

Turkey's army staged two dozen large-scale incursions into northern Iraq between the late 1980s and 1997. The 1997 operation involved tens of thousands of soldiers and government-paid village guards.

While legislators took up the question of an attack into Iraq, Turkish troops supported by air power pressed ahead with an offensive in Turkey's Sirnak province close to the border. They targeted suspected escape routes for Kurdish guerrillas in the mountainous area.

Turks are furious that PKK rebels carry out attacks on Turkish soil and then slip across the border to sanctuaries in northern Iraq. Turkey has accused Iraqi Kurds of tolerating their ethnic brethren in the PKK.

Under intense pressure from leaders of Iraqi Kurds, Iraq's national government refused to allow Turkey to send troops across the border to chase the rebels under a counterterrorism pact the two countries signed in September.

Turkey does have potential nonmilitary weapons. It could close its border crossings with northern Iraq, which are major source of business for the Iraqi Kurd economy.

But the latest string of attacks by the PKK ramped up public pressure on Erdogan, who has been accused by the opposition of lacking determination to act.

"America is going 10,000 kilometers (6,200 miles) to hunt down terrorists in Iraq and Afghanistan. But we can't go 30 kilometers (20 miles), we cannot step into northern Iraq?" complained Abdulmuttalip Hanedan, a village guard leader in Sirnak.