MIRANSHAH (Pakistan) - US DRONE strikes targeted militant vehicles in Pakistan's north-western tribal belt on Sunday, killing nine Islamist fighters, security officials said.

Two missiles were fired at a vehicle soon after it left a militant compound near Miranshah, the main town in the North Waziristan province, a security official said.

'The attack blew up the vehicle and also damaged the compound. Five militants were killed, they had been inside the vehicle, which was destroyed in the attack,' the official said from Miranshah.

Another official, in the city of Peshawar, said the pilotless aircraft fired four missiles in two separate raids on the car in Dandey Saidgai village, confirming the deaths of five militants. A drone then fired two missiles at a car in Moizer town, 40km west of Miranshah, officials said. 'Four militants were killed as the attack blew up their car in a fireball,' an official said.

Two other other security officials confirmed the attack and the casualties. The region is considered a fortress for Taleban and Al-Qaeda-linked fighters and the focus of a dramatic increase in US drone strikes.

It was not immediately clear if the drones were chasing any high value target, officials said. A covert US drone campaign in Pakistan has stepped up strikes in the tribal belt, as intelligence claims emerged last month of a Mumbai-style terror plot to launch commando attacks on European cities.

Drone strikes kill 9 militants