Pakistani fighter jets have launched airstrikes against militant hideouts in the country's troubled northwest, killing up to 100 insurgents.

The strikes targeted the mountainous Dehgan area, 25km west of Miranshah, the main town of North Waziristan tribal district.

The area is known to be a stronghold for Taliban and al-Qaeda linked militants on the border with Afghanistan.

No exact number of the militants killed in airstrikes was immediately available. The strikes took place overnight in a remote location. 

But officials said that as many as 100 were killed.

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

The airstrikes come a week after militants conducted an all-night siege of Karachi airport, killing 38 people. 

The Pakistani Taliban and the Islamic Movement of Uzbekistan later said Uzbek fighters took part in the assault which also resulted in the deaths of ten militants.