The latest clashes in the lawless North Waziristan tribal agency bordering Afghanistan came as pro-Taliban groups there warned Pakistani soldiers to quit fighting or face the "gift of death" through new suicide attacks.

Washington has intensified pressure on Islamabad to step up military action, warning it may launch strikes there -- comments Pakistan called "irresponsible and dangerous."

The US military has offered to provide air support and "supporting fires" for Pakistani military operations against al-Qaeda but in the past has been rebuffed, US defence officials said Monday.

General Peter Pace, the chairman of the Joint Chiefs of Staff, disclosed the offer of US military and intelligence assistance on Friday in a meeting in Schweinfurt, Germany with family members of US troops.

Pace's comments were first reported by a CNN correspondent travelling with the general. Defence officials on Monday confirmed his remarks but said the offer was not new, but rather of a longstanding character.

A US defence official who was present at the meeting in Germany said Pace talked about US military and intelligence assistance to Pakistan in the context of a long relationship with Pakistani President Pervez Musharraf.

"He did say 'kinetic.' He also said 'intel sharing,'" said the official, referring to notes.

The official said that when asked later what he meant by "kinetic," Pace said, "Air support, supporting fires. If he (Musharraf) were to ask, we would see how we might be able to help. I'm not predicting anything.'"

Pace said the offer did not include US ground troops.

Islamic militants kidnapped two Pakistani soldiers from a troubled tribal region, slit their throats and dumped the bodies with a warning note to others, officials said Tuesday.

The soldiers from the paramilitary Frontier Corps were abducted late Monday from a checkpost near Khar, the main town in the northwestern Bajaur tribal district bordering Afghanistan, local official Sardar Yusuf told AFP.

The militants slashed their throats and dumped the bodies near a bazaar early Tuesday, with a note saying "Those who support Musharraf and Bush will meet this fate", he said.

A wave of Islamist suicide attacks has claimed over 200 lives in Pakistan since US-ally President Pervez Musharraf ordered a raid on the pro-Taliban Red Mosque in the capital on July 10-11 and vowed to uproot extremism.

Amid a recent troop build-up in the troubled northwest, militants in North Waziristan eight days earlier tore up a shaky truce reached with the government last September, launching a spate of new attacks.

Pakistan's chief military spokesman Major General Waheed Arshad told AFP Monday that at least 30 rebels died in a series of clashes since late Sunday, and five more were killed in a battle that continued Monday evening.

Two soldiers had been killed and another 12 wounded in the violence over the past 24 hours, he added, but gave no further details.

A peace delegation made up of Pashtun elders from Pakistan's six other semi-autonomous tribal agencies returned empty handed late Sunday but was scheduled to resume talks Tuesday in Miranshah, North Waziristan's main town.

However, pamphlets distributed there Monday did not bode well for peace.

Entitled "Till Islam Lives in Islamabad" and signed by a group calling itself the Mujahedin-e-Islam (Islamic holy warriors), they threatened that suicide bombs would again bring Pakistani soldiers the "gift of death."

They warned that suicide attackers "love death more than you love your 5,000-rupee salary, nude pictures of Indian actresses and liquor."

"We know that you have become America's slave and are serving infidel (non-believer) Musharraf and have become a traitor to your religion for food, clothes and shelter."

Another 19 rebels were killed in weekend clashes in North Waziristan.

The truce, signed in September, was heavily criticised by Washington and Kabul. Militants tore it up amid complaints about new military checkpoints and a lack of compensation for damage in previous army operations.

Washington has said the truce was a failure that allowed al-Qaeda and the Taliban to regroup across the border from war-torn Afghanistan, and has warned it was considering military strikes against them inside Pakistani territory.

US national intelligence chief Mike McConnell earlier said he believed al-Qaeda chief Osama bin Laden was alive and sheltering in the frontier zone.

White House Homeland Security Adviser Frances Townsend told CNN: "No question that we will use any instrument at our disposal to deal with the problem of Osama bin Laden and (his deputy Ayman al) Zawahiri and al-Qaeda."

Pakistani foreign ministry spokeswoman Tasnim Aslam on Monday called the latest comments from Washington "irresponsible and dangerous."

"We have stated in the clearest terms that any attack inside our territory would be unacceptable," she told a weekly media briefing.

"We do not want our efforts to be undermined by any ill-conceived action from any quarter that is inconsistent with the principles of international law and would be deeply resented in the tribal areas and generally in Pakistan."