An explosion rocked a central Iraqi town on Sunday, and witnesses said there were casualties.

The explosion occurred outside a police station in Suwayrah (search), 30 miles south of Baghdad, the witnesses said. They said there were some casualties but this could not be independently confirmed.

No other details were available.

Suwayrah is part of the so-called Sunni Triangle (searchin central Iraq, the stronghold of Saddam Hussein loyalists who are fighting U.S.-led coalition forces and their Iraqi allies.

The insurgents have carried out frequent attacks on police stations since the Iraqi police force was reconstituted last year. More than 300 policemen have been killed, according to U.S. military commanders.