A bomb attack claimed by the Taliban has destroyed 22 fuel tankers carrying supplies for NATO forces in Afghanistan, local officials have said."At 2am the Mujahideen attacked the invader NATO trucks,” the Taliban said in a statement on Wednesday.A magnetic bomb stuck to the side of a truck triggered a series of powerful explosions in what were mainly fuel tankers parked overnight at a rest stop in Samangan in northern Afghanistan, Afghan officials said.The pre-dawn fire engulfed the trucks, which were on their way from Uzbekistan toward NATO forces in the south, said Ghulam Sakhi Baghlani, Samangan deputy governor."The first explosion resulted in a fire which quickly engulfed as many 22 trucks,” he said, adding that three drivers were also injured in the blaze.NATO was forced to make greater use of more expensive northern supply routes after Pakistan banned its convoys following a botched US airstrike which killed 24 Pakistani soldiers last November.Taliban members fighting to overthrow the Western-backed government of President Hamid Karzai claimed responsibility for the tanker attack, saying several private guards were killed.A spokesman for NATO’s International Security Assistance Force (ISAF) said initial reports showed 24 tankers were destroyed after an improvised bomb attack.But he said he could not immediately confirm that the civilian tankers were carrying fuel for ISAF, which relies on contractors to move many of its supplies.Pakistan lifted its blockade on NATO supplies earlier this month, but only a few trucks have actually crossed the border.Owners say they are waiting for compensation and security guarantees in the face of Taliban threats before resuming journeys from the port of Karachi to the Afghan border.Brigadier General Gunter Katz, an ISAF spokesman, said this week that there had been an increase in attacks in Afghanistan."Generally, in the past 12 weeks, we have a slight increase [of] 10 per cent, of insurgent attacks on Afghan security forces and international troops,” he told a news conference.