Five U.S. troops were killed after a US military helicopter crashed in the Mediterranean

Five U.S. troops are dead after an American military helicopter crashed in the eastern Mediterranean Sea on Friday evening, U.S. officials confirmed Sunday

The crew was conducting a “routine air refueling mission” during a training sortie when their aircraft suffered a mishap, U.S. European Command said in an emailed statement. All aboard were killed.

The command first announced the accident on Saturday but declined to say what type of aircraft was involved.

Defense Secretary Lloyd Austin confirmed the downed asset was a helicopter in a statement on Sunday. The Pentagon has not specified to which branch of the armed forces the aircraft belonged.

“While we continue to gather more information about this deadly crash, it is another stark reminder that the brave men and women who defend our great nation put their lives on the line each and every day to keep our country safe,” Austin said. “They represent the best of America. We will remember their service and their sacrifice.”

The mishap prompted an “immediate” rescue effort that included nearby U.S. military aircraft and ships, European Command said.

The command did not provide further details about where in the region the plane went down.

However, the U.S. issued a flight notice early Saturday noting a “search-and-rescue operation in progress” in the span of sea between Cyprus and Lebanon.

Among those forces are the Navy’s Ford carrier strike group stationed in the eastern Mediterranean, U.S. surveillance aircraft gathering intelligence off of the Israeli coast and others spread around the region. The Eisenhower carrier strike group also passed through the Mediterranean on its way to the Red Sea earlier this month.

The military is investigating the cause of the mishap. It will not release the names of the deceased until 24 hours after their families have been notified, in accordance with Pentagon policy.

“Our thoughts and prayers are with the families of the fallen,” European Command said.

Lebanon’s el Nashra website reported the following about the incident:

“The Washington Post newspaper revealed that “the American soldiers who were killed when their plane crashed over the Mediterranean Sea were conducting training in Cyprus to evacuate their nationals from Lebanon.”