Iran’s Islamic Revolutionary Guard Corps said the U.S. drone used to kill a top Iranian general in Baghdad took off from a military base in Kuwait, the semi-official Fars news agency reported, citing Brigadier General Amirali Hajizadeh, the commander of the Guards’ aerospace force.

The Guards had detected activity from the drone and fighter jets near Baghdad airport but didn’t know they were planning to target Qassem Soleimani, according to Hajizadeh. At least four military bases in the Persian Gulf were involved in the Jan. 3 operation, he said, according to the report late Wednesday.