MAMAD GAT, Pakistan -- A top Pakistani army commander said Wednesday that his military has no imminent plans to launch an offensive in a tribal region home to numerous militants who focus on attacking U.S. and NATO forces in neighboring Afghanistan.

The statement by Lt. Gen. Asif Yasin Malik contradicted rampant media speculation that an operation in North Waziristan was in the works after years of requests for it from the United States.

Malik's dismissal came as police said a cross-border insurgent attack elsewhere in the northwest killed five security troops on Wednesday.

The general oversees military operations in the tribal areas and other parts of the northwest bordering Afghanistan. He spoke to reporters on a military-hosted trip to Mohmand, one of the tribal regions where the army has attacked Taliban and other Islamist extremists.

His reasoning for holding off on an offensive in North Waziristan was the same advanced by other army officials in recent years -- that Pakistani troops are too stretched going after insurgents elsewhere.

Unlike the major militant groups in North Waziristan, the insurgent groups Pakistan has targeted tend to stage most of their attacks inside Pakistan.

"There is no change in North Waziristan in past months and weeks," Malik said. "We will undertake an operation when we want to, when it's in the national interest."

Local media reports have recently suggested that Pakistan may have been persuaded to carry out a limited operation in North Waziristan soon as a means of rebuilding ties with the United States, which have been badly damaged by the May 2 American raid that killed Osama bin Laden.

Pakistani leaders insist they had no idea the al-Qaida chief was hiding in the northwest garrison city of Abbottabad. But they have called the unilateral U.S. incursion a violation of their sovereignty.

Top U.S. officials say there's no evidence that the upper echelons of Pakistani military and civilian leadership knew bin Laden's whereabouts, but suspicions persist that some elements in lower ranks of the security forces may have helped harbor the terrorist leader.

Since the bin Laden attack, a wave of bloodshed has swept Pakistan. Several of the attacks have been claimed by the Pakistani Taliban -- one of the groups the army is moving against -- who say they are avenging bin Laden.

Around noon Wednesday, some 200 militants streamed over the border from Afghanistan and attacked a Pakistani checkpoint in Upper Dir district, killing at least five security troops, police official Bahadur Khan said.

The incident underscored the dangers posed by the porous nature of the Pakistan-Afghanistan border, which both countries have struggled to control as a means of stopping al-Qaida and Taliban-led insurgent movements who have ties on both sides of the boundary.

Upper Dir lies just outside of Pakistan's tribal areas, but it, too, has witnessed militant activity, and the Pakistani military has carried out operations there in the past. The attack Wednesday in Shaltalo town was likely a reaction to those offensives.

The area is remote and dangerous, making it difficult to independently verify information.

Also Wednesday, a helicopter carrying a top army officer crashed in the Indus river near Kot Sultan Bhakri town in Pakistan's Punjab province. All aboard were feared dead.

Maj. Gen. Mohammed Nawaz, who commanded the paramilitary border guards known as the Punjab Rangers, was in the chopper when it went down, said Mushtaq Anjum, a senior government official. Nawaz's area of responsibility included the border with archrival India.

A military official also confirmed that Nawaz was onboard. He requested anonymity because he was not authorized to speak to media.

It was unclear how many other people were on the aircraft. The reason for the crash was under investigation.