In an overnight raid, French fighter jets destroyed 12 Iraqi buildings used as an arms depot by the Islamic State militants, France's military chief said Friday.

"Tonight we undertook a big operation in Iraq in which we destroyed buildings in which Daesh (Islamic State) was producing traps, bombs, arms to attack the Iraqi forces," France's Chief of Staff of Armed Forces Pierre de Villiers told Europe 1 radio, reports Reuters.

De Villiers said that altogether 70 bombs were dropped by the Coalition forces, including 12 dropped by France. The airstrikes completely destroyed its targets, he said without mentioning the location of the operation.

France's military has also announced airstrikes in Fallujah and Mount Sinjar, where militants had encircled thousands of Yazidis.

In addition to air strikes and conducting reconnaissance missions, the French operations in Iraq have also included giving training to Iraqi forces and delivering equipment to Kurdish fighters in the country's north.

France was the first country to join the U.S.-led coalition to conduct air strikes against the Islamic State militants in Iraq.

Meanwhile, Iraqi officials said that Islamic State militants used chlorine gas while fighting with Iraqi security forces and Shiite militiamen in north of Baghdad last month, reports the Associated Press.

A senior security official and an official from the town of Duluiya said that the militants used bombs with chlorine-filled cylinders. An official from the town of Balad also confirmed that the militants used chlorine gas during the fight.

In the assault by the militants, around 49 troops and Shiite militiamen were affected by the chlorine gas to some extent and displayed symptoms consistent with chlorine poisoning, such as difficulty in breathing and coughing, the three officials said.

The senior security official said that the Islamic State fighters probably got the chlorine from water purification plants located in the areas they had captured earlier.

"The IS fighters seized some quantities of chlorine after seizing control of some water purification plants or sites where chlorine was kept," said the senior official, adding that the "IS group has some experts who were able to manufacture chlorine shells," reports AP.