The U.S. Embassy in Jordan has issued a warning to citizens that "high-end malls" in Jordan's capital could be attacked as the kingdom takes part in airstrikes targeting the extremist Islamic State group.

The embassy's statement Wednesday night did not elaborate on the threat to Amman, though it said it was "judged to be credible." It said Jordan's government "has taken steps to increase security at these locations."

There was no immediate comment from Jordanian officials.

The Islamic State group, which controls about a third of Syria and Iraq, burned a captive Jordanian pilot to death earlier this month, sparking widespread anger across the kingdom. In an initial response, Jordan executed two Iraqi al-Qaida prisoners and immediately launched airstrikes against the group.