Blasts and bullet killed at least 21 people in Iraq on Wednesday, among them 12 died when a powerful booby-trap flattened building in northern Mosul city, police and the US military said.
More than 142 people were wounded in the violence, most of them residents of houses adjoining the booby-trapped building in western Mosul which were damaged in the explosion, officials said.
An Iraqi security official said the three-story empty building was being readied by the Iraqi army for use as a snipers' post to stop Al-Qaeda fighters using a nearby bridge to hang victims of their kidnappings -- one of their favoured execution spots.
"A large house-borne bomb exploded" in Mosul, a US military statement said. "Our numbers (are) 32 wounded Iraqis and 2 Iraqis killed. Three Iraqi soldier were also wounded," it said.
The statement said the last also knocked out several cell phone towers in Mosul.
Iraqi police Brigadier General Abdul al-Juburi earlier said the blast occurred when a munitions cache in the building exploded.
"The Iraqi army received reports that a cache of weapons and munitions had been discovered in an empty building in west Mosul. The army arrived near the area and was waiting for the disposal experts to arrive when the explosion occurred," Juburi told AFP.
"The force of the blast caused the building to collapse.