U.S. President Barack Obama sent a letter to Congress Sunday notifying members he had authorized airstrikes on the Mosul dam to help Iraqi forces retake control. The White House statement said the order was consistent with the War Powers Act.

"Failure of the Mosul dam could threaten the lives of large numbers of civilians, threaten U.S. personnel and facilities -- including the U.S. Embassy in Baghdad -- and prevent the Iraqi government from providing critical services to the Iraqi populace," the statement said.

"These operations are limited in their nature, duration, and scope and are being undertaken in coordination with and at the request of the government of Iraq."