U.S. targets in Iraq and Syria have been attacked at least 24 times since Oct. 17, a senior U.S. defense official said Monday.

The attacks have been conducted primarily with rockets and drones, the official said, and 15 have been against U.S. targets in Iraq and nine against U.S. bases in Syria. The official did not report any U.S. injuries.

At least five of the attacks have come since the U.S. launched retaliatory strikes on two Iranian-linked targets in Syria on Thursday.

A senior U.S. military official said that the two locations hit by the U.S. were a weapons storage area and an ammunition storage area and that the U.S. used precision munitions dropped by two F-16s. No casualties were detected, the senior defense official said.