The US military has said that a huge fire at an army base's ammunitions store in the Iraqi capital was caused by a mortar fired by insurgents.
The explosions were seen for miles around the city
The fire, which set off a series of blasts and explosions at the base, caused no casualties or injuries.
The BBC's Andrew North, in Baghdad, said the explosions started at about 2300 (2100 BST) on Tuesday night.
Blasts from the base, in the city's south, were heard for miles. The fire continued to burn through the night.
"Intelligence indicates that civilians aligned with a militia organisation were responsible for last night's mortar attack," Base spokesman Lt Col Jonathan Withington said.
Earlier, an insurgent group had posted a statement on the internet, claiming responsibility for the attack.
The US military spokesman said that all troops and workers on the base had been safely evacuated to bomb shelters to protect them from the blasts.
He said no-one had been injured in the explosions.
The Iraqi Interior Ministry said the blasts had shaken three neighbourhoods close to the base in the southern district of Doura.