BAGHDAD — Five senior Islamic State officials have been captured, including a top aide to the group’s leader, in a complex cross-border sting carried out by Iraqi and American intelligence, two Iraqi officials said Wednesday.

The three-month operation, which tracked a group of senior Islamic State leaders who had been hiding in Syria and Turkey, represents a significant intelligence victory for the American-led coalition fighting the extremist group and underscores the strengthening relationship between Washington and Baghdad.

Two Iraqi intelligence officials said those captured included four Iraqis and one Syrian whose responsibilities included governing the Islamic State’s territory around Deir al-Zour, Syria, directing internal security and running the administrative body that oversees religious rulings.

Iraq’s external intelligence agency published a statement confirming the arrests, but did not mention any details of the role played by the Americans or the Turks. The two Iraqi intelligence officials spoke on condition of anonymity to discuss details that had not been made public.