Pakistani intelligence officials say that military air strikes overnight in the northwestern tribal regions bordering Afghanistan have killed dozens of fighters. Local officials said the attacks on Sunday targeted hideouts of armed groups in the North Waziristan tribal area. No precise death toll from the air strikes was immediately available, but a local security official told the AFP news agency that "dozens of militants have been killed and eight of their hideouts have been destroyed". Al Jazeera's Kamal Hyder, reporting from the northern city of Peshawar, said that "several militias were attacked, including Uzbeks responsible for carrying out attack on Karachi airport". The air strikes came a week after a group of fighters attacked the airport in the port city in a five-hour siege that left 36 people dead, including the 10 attackers. Uzbek fighters and the Pakistani Taliban both claimed responsibility for the airport attack, and the Pakistani Taliban said the two had worked together to carry it out, marking an increase of armed groups working together. Pressure has been mounting on the Pakistani government to launch a ground offensive in the Taliban stronghold of North Waziristan. The air strikes were the second time this week the military has hit the tribal regions. Following the brazen assault in Karachi, the US carried out two drone strikes in the region on Wednesday, the first time the controversial drone programme has been used this year.