Syria is preparing to send fighters to Saudi Arabia to deploy along its border and potentially help it fight Iranian-backed rebels in neighboring Yemen, three officials with knowledge of the plans told The Associated Press.

Syrian military advisers have already deployed to Saudi Arabia, but no fighters have been sent to Yemen, according to a regional official and two Syrian officials, all of whom spoke on condition of anonymity because they were not authorized to comment publicly.

Officials in Saudi Arabia did not immediately respond to requests for comment.