Five US service members have been killed on a routine training mission after the military aircraft carrying them suffered a "mishap" and crashed into the sea.
The military personnel were taking part in a routine air refuelling mission in the eastern Mediterranean Sea on Friday as part of their training, the US defence department confirmed on Sunday.
The tragedy was reported by the United States European Command (USEUCO), which handles American military operations in Europe and parts of the Middle East.
It said in a statement: "All five of the service members on board the aircraft were killed."
Search and rescue teams were deployed immediately after the incident, including nearby US military aircraft and ships.
An investigation into the crash is now under way.
"We can definitively say that the aircraft sortie was purely related to training and there are no indications of hostile activity," the USEUCO statement said.
The identities of the deceased crew members will not be released for 24 hours while officials inform their next of kin, "out of respect for the affected families" and in accordance with the US Department of Defence policy.
"Our thoughts and prayers are with the families of the fallen," USEUCO added.
The US military has deployed two aircraft carriers - the Ford and the Eisenhower - together with their supporting ships and dozens of aircraft to the eastern Mediterranean since the deadly Hamas attack in Israel on 7 October, to act as a deterrent in the hope the conflict does not expand.
The tragedy was confirmed as people across the US prepared to mark Veteran's Day - known as Armistice Day in the UK - on Saturday.
It is not yet clear what military service the aircraft belonged to.
In a statement, US President Joe Biden said he and first lady Jill were mourning the loss of the five service members.
'Servicemen represent the best of America'
"Our service members put their lives on the line for our country every day," he said.
"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."
Mr Biden said he and his wife were praying for the families and friends who have "lost a precious loved one - a piece of their soul".
"Our entire nation shares their grief," he added.
"And, during this weekend when we pause to honour our nation's veterans, we once more affirm the sacred obligation we bear to those who volunteer to serve our nation as well as their families, caregivers, and survivors.
"We pray for the families of all our fallen warriors today and every day."
US secretary of defence, Lloyd J Austin III, said the servicemen "represent the best of America".
"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.
"We will remember their service and their sacrifice.
"My prayers are with the patriots we have lost today and their families, loved ones, and teammates."