Iraqi authorities say the police chief of the northern city of Mosul has been killed in a suicide bomb attack as he was touring the site of Wednesday's massive explosion that killed at least 18 people.

Officials say the attacker in a police uniform walked up to the police chief Brig. Gen. Falih Mohammed Hassan and then detonated his explosives vest. The police chief was rushed to a nearby hospital, where he later died.

At least two policemen were killed and several other people were wounded in the blast.

Meanwhile, rescue teams and police in Mosul are continuing to search for victims in the rubble of buildings and houses flattened by Wednesdays' blast, which occurred after police were tipped off about a weapons cache inside a vacant building. It is not clear what triggered the explosion.

Separately, two Iraqi policemen were killed when a roadside bomb blast hit their patrol in central Baghdad Thursday.

Some information for this report was provided by AFP, AP and Reuters.