Pakistani police say an explosion has rocked a market in a northwest district next to the troubled Swat Valley.

Police official Tahir Khan says casualties are feared in the Monday blast, which may have been a car bombing.

The explosion occurred in Shangla, a district east of Swat.

It is the latest in a string of explosions and attacks in the country, signaling the Taliban are still strong.

Swat has been the focus of an intense military offensive against the Taliban. The army says it has largely cleared the valley of the insurgents, though some were on the run.

Many of the Taliban are believed to have melted into the rural areas or gone to neighboring districts.