Two explosions in a Baghdad mosque killed at least 18 worshippers on Wednesday, including two children, security officials said.
They said the blasts in the mostly Shiite district of Sadr City district also injured more than 90 people, almost completely destroyed the building and damaged several nearby houses.
The government said the blasts occurred at a weapons depot in Sadr City. It said an investigation was under way to determine the cause of the explosions but did not give the exact location of the depot.
Earlier, state television cited a ministry spokesman describing the explosion as "a terrorist aggression on civilians", which had caused "martyrs and wounded".
Authorities did not offer an explanation of the discrepancies between the two statements, neither of which gave casualty figures.
The officials said weapons were stored inside the mosque, which is frequented by supporters of Muqtada Al Sadr, the Shiite cleric whose supporters opposed American troops in the years after the US-led invasion of Iraq in 2003.
Mr Al Sadr’s followers won the largest number of seats in Iraq’s May 12 parliamentary elections but would have to form a coalition government with other blocs in a process that could drag on for months.
He also commands a government-backed paramilitary force, which took part in the nearly three-year war against ISIS.
Iraq declared victory over ISIS last year, but the extremist group retains pockets in western and northern Iraq and continues to attack security forces.
In May, two homemade bombs targeted the headquarters of the Iraqi Communist Party, which is part of Mr Al Sadr's bloc.