At least nine people have been killed and 75 others wounded in a blast at a residential building in Iraq's northern city of Mosul, according to police.
Witnesses to Wednesday's blast said it was one of the biggest explosions to hit Mosul, the capital of Ninawa province and 390km north of Baghdad.
Brigadier-General Abdul Kareem al-Jubouri, the head of the operations room in the Mosul police command, said police had been tipped off that the building contained a large stock of weapons.
The blast appeared to have been caused when the munitions blew up.
Building collapses
"The Iraqi army received reports that a cache of weapons and munitions had been discovered in an empty building in west Mosul," al-Jubouri said.
"The army arrived near the area and were waiting for the disposal experts to arrive when the explosion occurred."
Al-Jubouri said: "The force of the blast caused the building to collapse. Fifteen houses next to it were damaged."
US and Iraqi forces sealed off the area while rescuers hunted through the rubble for those caught up in the blast, he said.
Ninawa province is one of several northern regions where al-Qaeda in Iraq fighters have regrouped after being pushed out of Baghdad and western Anbar province last year.
Over the last month, the US military has been carrying out large-scale offensives in Iraq's northern provinces against al-Qaeda.