The attack came shortly after Pakistan's ambassador to the US Husain Haqqani vowed his country will go after terrorists on its soil.

Naeem Iqbal, a police spokesman, said five people are wounded in the attack on tankers parked on a main road outside a housing complex near the capital city of Islamabad. Efforts to put out the blaze are ongoing, he said.

Bin Yamin, a deputy police chief, said eight gunmen enter the area around 12:15am local time. They tell people near the trucks to run away and that most do. Then they open fire.

The tankers are parked in the vicinity of an oil refinery where they were going to go to pick up fuel for NATO forces in Afghanistan, Yamin said.

Video images of the scene showed firefighters working to put out flames that stood out in the night against the overturned trucks.