WASHINGTON (AP) - The U.S. military has shot down a Syrian Air Force fighter jet that bombed local forces aligned with the Americans in the fight against Islamic State militants. The action appears to mark a new escalation of the conflict.

A Pentagon spokesman says the U.S. had not shot down a Syrian regime aircraft before Sunday's confrontation.

The U.S. has long said that it would protect what it calls moderate Syrian opposition forces. This is the first time it resorted to engaging in air-to-air combat to make good on that promise.

The U.S.-led coalition headquarters in Iraq says a U.S. F-18 Super Hornet shot down a Syrian government SU-22 after it dropped bombs near the U.S. partner forces. The shootdown was near the Syrian town of Tabqa.

Copyright 2017 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.