A bo mb blast late 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 said. "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.