MIRANSHAH, Pakistan (AFP) - Pakistani fighter jets launched air strikes early Sunday against militant hideouts in the country's troubled northwest, killing more than 50 insurgents, the Pakistan military said.

However local security officials put the death toll far higher, saying that about 150 militants died in the air strikes, which primarily targeted Uzbek fighters in a remote area of tribal North Waziristan.

Among the dead were insurgents linked to last Monday's all-night siege of Karachi airport that killed 38 people, including 10 attackers, and all but destroyed a tentative peace process between the Pakistani Taliban (TTP) and the government.

The mountainous Dehgan area, some 25 kilometres west of the main town of Miranshah in North Waziristan, is a stronghold for Taleban and Al Qaeda-linked militants on the border with Afghanistan.

"Today at about 0130 hours (430am Singapore time), a number of terrorist hideouts in Dehgan, Datta Khel in North Waziristan were targeted by jet aircraft. Over 50 terrorists, mostly Uzbek foreigners, were killed in the strikes," a statement from the Pakistani military said.

"There were confirmed reports of presence of foreign and local terrorists in these hideouts who were linked to the planning of the Karachi airport attack," it said.

However local security officials in Miranshah, who spoke to AFP on the condition of anonymity, put the death toll far higher than the official toll.

"Up to 150 people were killed during the strikes early Sunday. These strikes were carried out based on confirmed reports about the presence of Uzbek and other militants in the area," an intelligence official said.

Another security official said that "the number of the killed people was even more than 150".

The Pakistan military has not confirmed the higher figure.

However, the military statement said "an ammunition dump had also been destroyed during the strikes and that further details would follow", suggesting the death toll could rise.

Pressure has been mounting on the Pakistani government to launch a ground offensive in the Taleban-infested North Waziristan tribal district.

Following the brazen assault in Karachi, the US carried out two drone strikes in North Waziristan on Wednesday, the first time the controversial programme has been used this year.

The same day, Pakistani air force jets pounded suspected militant hideouts, leaving at least 25 dead.

No precise number death toll from Sunday's air strikes was immediately available as they took place overnight in a remote location.

There were competing reports about the identity of those killed. But a second intelligence official in Miranshah told AFP that Uzbek fighters were targeted.

"Uzbek fighters had gathered in the area, they were taking rest when jets hit them," he said, adding that hideouts of local Taleban and other foreign fighters were also targeted.

Both the Pakistani Taleban and the Islamic Movement of Uzbekistan - an Al-Qaeda affiliate mainly based in Pakistan's tribal belt - said Uzbek fighters took part in the Karachi airport assault.

Locals in Pakistan's tribal regions say some of the world's most feared Islamist fighters are quietly slipping away from the area in anticipation of an increase in military operations against them.

Rumours of a ground offensive in North Waziristan, one of seven tribal regions along the border, have abounded for years. But authorities have held back from a final push - possibly fearing the blowback in Pakistan's major cities such as Karachi.

But the past week has seen a significant increase in air strikes and renewed drone attacks.

Washington reportedly suspended its drone programme in December to give Islamabad time to pursue peace talks with the TTP aimed at ending a seven-year insurgency that has claimed thousands of lives.

The dialogue resulted in a month-long ceasefire between March and April, but later broke down, with Pakistan resuming air strikes on suspected militant hideouts in the tribal areas.

The army was widely seen as being opposed to the dialogue because of the heavy casualties it has sustained at the hands of the TTP, which views them as a mercenary force serving foreign interests.

But following the breakdown of the talks and the Karachi attack, observers believe both civil and military authorities are converging on the need for more concerted action.