A military helicopter with U.S. service members aboard crashed in Iraq late Thursday, U.S. Central Command and military officials said.

"A U.S. military aircraft has crashed in western Iraq with U.S. service members aboard," CENTCOM said in a statement. Rescue teams were sent to the scene soon after the crash.

The number of service members on board and the cause of the crash was not immediately clear. The military said the aircraft crashed in the vicinity of Al Qaim, which is in Anbar province near the Syrian border.

Early indications were that there was no enemy fire involved, officials told NBC News.

"While the investigation is still ongoing, there is absolutely no reason to believe this involved enemy action," said Col. Thomas Veale, a spokesman for the U.S.-led coalition battling the Islamic State. "All indications are this was an accident during a routine troop movement. The department of defense will release casualty details after next of kin notifications are complete."

Defense Secretary James Mattis is aware of the incident, a spokesperson said.

The coalition battling ISIS insurgents in Iraq and Syria have an outpost in Qaim, which is located near the Syrian border, the Associated Press reported.

Prime Minister Haider al-Abadi declared victory over the ISIS in Mosul in July. In the following months Iraqi forces retook a handful of other Islamic State-held towns including Tal Afar in August, Hawija in September and Qaim in October. In November, Iraqi forces retook the last Iraqi town held by Islamic State — Rawah, near the border with Syria.

The U.S.-led coalition has continued to work with Iraq and Syrian Democratic Forces to shore up the border region to make sure that foreign fighters and insurgents can't move freely across the region.