BAGHDAD, June 6 (Xinhua) -- The death toll of a huge explosion in eastern Baghdad on Wednesday rose to 18, while more than 90 others were wounded, an Interior Ministry source said.

"The latest report said that 18 people were killed and more than 90 others were wounded by the huge explosion of an explosive cache in eastern Baghdad," the source told Xinhua on condition of anonymity.

The blast occurred in the evening when an explosive cache at a house used as a warehouse went off near a Shiite mosque in the Shiite bastion of Sadr City neighborhood, a stronghold of nationalist cleric Moqtada al-Sadr, whose party won the May 12 parliamentary election, the source said.

The house was totally destroyed and five nearby houses were badly damaged, the source said, without giving further details about which militia owns the house.

Earlier, the source put the toll at three civilian killed and 12 others injured by a car bomb explosion in the Sadr City neighborhood.

Security authorities have opened an investigation into the explosion to determine if it was an accident or a terror attack.