The U.S.-led coalition against Islamic State last month dropped the most bombs in its 16-month campaign in Iraq and Syria, according to new Air Force data.

The 3,271 munitions used in November were almost double the 1,683 in June, the low point of this year. They bring to almost 32,000 the weapons — most of them precision-guided — dropped by fighters, B-1B bombers and drones in almost 11,000 combat sorties since August 2014, according to statistics compiled by U.S. Air Forces Central Command that were obtained by Bloomberg News in advance of publication.

President Barack Obama has defended his strategy for combating Islamic State against criticism from Republicans in Congress and in the presidential campaign who say he's not being aggressive enough in the fight. Demands for a change in strategy increased after the terrorist attacks in Paris last month and the shooting rampage that killed 14 people in California on Wednesday, which is being treated by the FBI as a terrorism investigation.