U.S. Defense Secretary Lloyd Austin said in a statement: “We mourn the tragic loss of five U.S. service members during a training accident in the Mediterranean Sea early Saturday morning.”

“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,” he said.

European Command said that out of respect for the families of the service members and in line with Department of Defense policy, the identities of the crew members are being withheld for 24 hours until the families of those killed have been notified.

It wasn’t immediately clear which military service the aircraft belonged to. The Air Force has sent additional squadrons to the region and the USS Gerald R. Ford aircraft carrier, which has an array of aircraft on board, has also been operating in the eastern Mediterranean.

President Joe Biden issued a statement about the crash: “Today, Jill and I mourn the loss of 5 American service members who died when their aircraft crashed in the Mediterranean Sea during a routine training mission. Our service members put their lives on the line for our country every day. They willingly take risks to keep the American people safe and secure. And their daily bravery and selflessness is an enduring testament to what is best in our nation. Jill and I are praying for the families and friends who have lost a precious loved one — a piece of their soul. Our entire nation shares their grief.”