The death toll from a fire in Afghanistan's landmark alpine Salang tunnel rose to 31, a health ministry spokesman said on Monday.
Thirty-seven people were also injured in the accident in Salang Tunnel, located about 90 km (56 miles) north of Kabul, according to Sharafat Zaman, spokesperson for the Ministry of Public Health.
A fire, which the Ministry of Public Works said was caused by a fuel truck overturning, had torn through the tunnel on Saturday evening. The death toll was initially put at 12 after the fire was extinguished on Sunday, though officials had warned it could rise.
The tunnel remained closed to traffic on Monday and a spokesperson for the Ministry of Public Works said they would try to open it on Tuesday.
The 2.6 km (1.6 mile) 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 3,400 meters (11,000 feet).