At least 12 people were killed and 35 wounded when a bomb hit a market on Saturday in a mainly Shiite area of Pakistan's northwestern tribal belt, officials said.

The bomb hit the crowded vegetable market in Parachinar city, the capital of Kurram tribal district on the Afghan border where officials said the death toll was expected to rise.

"At least 12 people have been killed and 35 wounded," Ikramullah Khan, a senior government official in Parachinar, told AFP.