PESHAWAR, PAKISTAN (AFP) - A gas cylinder explosion in a passenger bus killed at least 13 people and wounded six others in northwestern Pakistan on Sunday (Jan 3), police said.

The bus, which was part of a wedding convoy, careered off the road and plunged into a ravine, triggering an explosion in a compressed natural gas (CNG) cylinder fuelling the vehicle in northwestern Karak district.

"The explosion killed 13 passengers including five women and five children," senior local police official, Ishtiaq Ahmad, said.

He added six passengers were injured.

Explosions in CNG fitted private and public transport vehicles are relatively common in Pakistan, often resulting in loss of life.