All seven service members aboard a U.S. helicopter that crashed in Iraq were killed, the Pentagon said Friday in a written statement.
The aircraft crashed in western Iraq a day earlier, said the officials, who insisted on speaking anonymously to release details of the crash before they were made public.
The crash did not appear to be the result of enemy activity and is under investigation, the Pentagon said.
"This tragedy reminds us of the risks our men and women face every day in service of our nations. We are thinking of the loved ones of these service members today," said U.S. Army Brig. Gen. Jonathan P. Braga, director of operations in the fight against the Islamic State extremist group in Iraq and Syria.
The helicopter was used by the Air Force for combat search and rescue and was shifting from one location to another when it went down Thursday afternoon near the town of Qaim in Anbar Province.
The Pentagon said an accompanying U.S. helicopter immediately reported the crash and a quick-reaction force comprised of Iraqi security forces and coalition members secured the scene.
The names of those killed would be released after next of kin are notified, the statement added.
New York City officials announced Friday that two of those killed were longtime members of the city's Fire Department — Lt. Christopher Raguso and fire marshal Christopher "Tripp" Zanetis. They were "truly two of New York City's bravest," Mayor Bill de Blasio said.
Zanetis received a law degree from Stanford in 2017.
President Donald Trump offered his thoughts and prayers on Twitter Friday for the families of service members killed, saying he was thinking of the "brave troops," and adding that "their sacrifice in service to our country will never be forgotten."
The U.S.-led coalition battling the Islamic State group in Iraq and Syria have an outpost in Qaim, which is located near the Syrian border. The anti-IS campaign accelerated through much of last year, as coalition and Iraqi forces battled to take back a string of cities and towns.
Prime Minister Haider al-Abadi declared victory over IS in Mosul in July. In the following months, Iraqi forces retook a handful of other IS-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 IS — 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.
Associated Press writers Susannah George in London and Lolita C. Baldor in Washington contributed to this report.