CIZRE, Turkey — Turkish warplanes and helicopter gunships reportedly attacked positions of Kurdish rebels just inside Turkey along the border with Iraq today, as Turkey’s military stepped up its anti-rebel operations.

Civilian and military leaders discussed the scope and duration of a possible cross-border offensive — a move that Turkey’s Western allies are trying to prevent.

An AP Television News cameraman saw attack helicopters and several F-16 warplanes loaded with bombs take off from an air base in the southeastern city of Diyarbakir. The warplanes and helicopter gunships bombed mountain paths used by rebels to infiltrate from neighboring Iraq, the official Anatolia news agency reported.

On Sunday, Turkish helicopter gunships penetrated into Iraqi territory and troops have shelled suspected Kurdish rebel positions across the border in Iraq, a government official said today.

American-made Cobra and Super Cobra attack helicopters chased Kurdish rebels three miles into Iraqi territory on Sunday but returned to their bases in Turkey after a rebel ambush killed 12 soldiers near the border, the official said on condition of anonymity because he was not authorized to speak to the media.

He also said Turkish artillery units shelled rebel positions as recently as last night but did not say which areas were targeted.

An AP Television News cameraman saw about a dozen transport helicopters fly along Mount Cudi, near the border with Iraq, today. He saw at least one warplane fly past Cizre, a town close to the Turkish-Iraqi border.

Some 18 miles east of Cizre, a tank battalion conducted military exercises. Soldiers established checkpoints on roads while troops looked for possible land mines.

In Washington, Pentagon officials said that they were aware of the reports, but could not confirm them.

“I don’t know of any Turkish airstrikes in that area today,” a Joint Chiefs of Staff operational planning director, Major General Richard Sherlock, told a Defense Department news conference today.

Officials were working to try to confirm the reports but could not confirm any bombing or ground activity on either side of the Iraq-Turkey border, another official said on condition of anonymity because he was not authorized to speak on the record.

Turkey, which has moved troops to the Iraq border, warned Iraq and Western allies yesterday that a large-scale incursion was imminent unless the American-backed government in Baghdad takes action against the rebels. The Turkish government said there would be no cease-fire with the fighters, who want an independent region in Turkey’s heavily Kurdish southeast.

About 100 red beret-wearing members of the official defense forces of Iraq’s Kurdish region were headed today for a camp near the border city of Dahuk, 260 miles northwest of Baghdad.

One of them, who would only identify himself as Captain Ziad, said his troops had been mobilized from Irbil, the capital of the autonomous Kurdish region in northern Iraq.

“We want to prevent the conflict in Turkey from coming across the border,” he said.

Turkey’s military and civilian leaders face growing demands at home to stage the offensive in northern Iraq, where the rebels of the Kurdistan Workers’ Party — known as the PKK — rest, train, and get supplies in relative safety before returning to Turkey to conduct attacks.

The chief of Turkey’s military, General Yasar Buyukanit, canceled a visit to Israel planned for the end of this month, private CNN-Turk television reported.

A high-level delegation from Iraq was expected to visit Ankara tomorrow.

Foreign Minister Ali Babacan of Turkey, returning late yesterday from Baghdad, said, “We said that we are expecting them to come with concrete proposals and otherwise the visit will have no meaning.”

Turkey has long pressed Iraq to capture and extradite rebel leaders and a senior Turkish government official said President Jalal Talabani of Iraq had told Mr. Babacan that Iraq “does not exclude extradition” of rebels.

Prime Minister al-Maliki of Iraq also has ordered the closure of all offices belonging to the PKK in Iraq and said they would not be allowed to operate in Iraqi territory. And America yesterday issued its most direct demand yet for anti-rebel measures from the government of Iraqi’s effectively autonomous Kurdish region.

“We need more than words,” Mr. Babacan said. “We said that preventing the PKK from using the Iraqi soil, an end to logistical support and all PKK activities inside Iraq and closing of its camps are needed. We also said its leaders need to be arrested and extradited to Turkey.”

Iraq’s parliament speaker today said his country cannot control the activities of Kurdish rebels but pledged to end any logistic support to the guerrilla group and seek a peaceful solution for the current standoff with Turkey.

“When the Iraqi government becomes capable of controlling Baghdad’s security, then the others can ask us to control the borders,” Parliament Speaker Mahmoud al-Mashhadani told reporters in Damascus after talks with his Syrian counterpart, Mahmoud al-Abrash.

However, he said, “this doesn’t absolve us from … a national duty not to serve as a headquarters or to support, in any form, any organization that might harm any neighboring country.”

Turkey’s foreign trade minister, Kursad Tuzmen, said his country could impose economic sanctions on northern Iraq to force the Iraqi Kurdish administration to cooperate with Turkey, Anatolia reported. Turkey provides electricity to northern Iraq, and most of the food sold in markets in northern Iraq comes from Turkey.

Adding to the tension is the alleged capture of eight Turkish soldiers who have been missing since Sunday’s ambush.