Afghan's Salang Tunnel explosion kills 12

"The Islamic Emirate expresses its deepest condolences to the families of the victims and ... it also calls on all relevant agencies to make more and serious efforts to prevent the recurrence of such terrible incidents," Ahmadi said.

Local broadcaster Tolo, citing the Ministry of Public Works, said a fuel truck had overturned and caught fire in the tunnel on Saturday night. The blaze had been extinguished on Sunday but the tunnel was closed to traffic and casualties could rise, according to the Ministry spokesperson.

The 2.6km long Soviet-built tunnel is a historic engineering feat that links Kabul and Afghanistan's north, connecting the Indian subcontinent to Central Asia through a treacherous mountain pass at 3400 metres.