**At least three people have been killed and eight injured by a blast in Mingora, the main city in Swat region in north-west Pakistan, police say.**Television footage showed black smoke billowing into the air and cars destroyed by the blast in a market.
It was not immediately clear what caused the explosion, which came as an army convoy was in the area. Some reports say there was also shooting.
Attacks have been rare in Swat since the army ousted militants last year.