A bomb blast late on Sunday in the western Pakistani city of Chaman near the Afghan border set ablaze several trucks loaded with supplies for NATO forces in Afghanistan, police said.
The bomb was planted under a tanker carrying fuel for NATO troops, which triggered the fire and quickly engulfed more than a dozen vehicles, Chaman police chief Sardar Hasan Musakhel told AFP.
"Right now, it is difficult to give the exact number of vehicles damaged by the fire because efforts are underway to extinguish the fire," Musakhel said, adding that there were no immediate reports of human casualties.
Chaman is one of two crossing points for supplies for US and NATO-led foreign forces fighting the insurgency in Afghanistan.
Musakhel said that hundreds of trucks, many loaded with NATO supplies, had been stuck on Pakistan's side of the border for the last two days due to a dispute with customs officials relating to inspection of goods.
He added that no one had claimed responsibility for the incident in Chaman, one of the main cities in the oil and gas rich Baluchistan province bordering Iran and Afghanistan.
A spokesman for the paramilitary Frontier Corps, Murtaza Baig, confirmed the incident.
Hundreds of people have died since Baluch insurgents rose up in 2004 demanding political autonomy and a greater share of profits from the region's natural resources.
Pakistan has been hit by a string of Taliban-related bomb blasts, as fears grow that Islamist extremists are exacting revenge for a military offensive against them in three northwestern districts.
The bulk of supplies and equipment required by foreign troops across the border is shipped through northwest Pakistan's tribal region of Khyber where Taliban militants have carried out a series of strikes on trucks.