Iraqi security officials said an explosion ripped through an arms depot belonging to an Iranian-backed militia faction north of Baghdad.
The explosion is the latest in a series of mysterious blasts that have rocked military bases and weapons depots around the country recently.
It was not immediately clear if there were casualties.
The blasts took place in bases and warehouses belonging to militia groups under the umbrella of the mainly Iran-backed militias known as the Popular Mobilization Forces.
The state-sanctioned PMF militias have fought alongside Iraq’s regular armed forces against the Islamic State group.
Some in Iraq have blamed the explosions on Israeli airstrikes and others on faulty storage but no one has claimed responsibility for the explosion near the Balad air base in Salaheddin province or the other explosions.