Image copyright Getty Images Image caption Defense Secretary Jim Mattis says the sailor had put in “in a long run of service”
The Navy SEAL team leader killed in a training accident in San Diego has been named as Jesse Vaughn, a decorated special warfare operator who served in Iraq and Afghanistan.
He died of head injuries in a training accident at Camp Pendleton.
The 29-year-old is the second service member killed in recent weeks in similar incidents in California and Nevada.
Two U.S. soldiers died in separate incidents in October after running into a restricted area while training.
Tests confirmed that Mr Vaughn was involved in a “training-related incident”, a Navy official said.
Military officials have said the conditions of both sailors were similar, and that the coroner’s reports will be released shortly.
Image copyright Getty Images Image caption President Donald Trump offered his condolences to the loved ones of fallen US service members
President Donald Trump said on Tuesday his “thoughts and prayers” were with the commando’s loved ones.
In his statement, Mr Trump said Mr Vaughn “put his life on the line for his country more than once in service to our nation”.
“He exemplified the professionalism, dedication and sacrifice of those who serve our country,” he added.
Mr Vaughn enlisted in the Navy in 2007, his official biography says. He went on to be an XO (executive officer) at both Naval Special Warfare Development Group, also known as SEAL Team Six, in the US Navy and as a special warfare operator.
He led SEAL Team Six in a raid in Yemen in January 2016, reports say.
In Afghanistan, he took over as executive officer in 2011.
Details on his burial have not yet been announced.
Read more: What training accidents mean for safety in the military
Risk remains high
The death rate for US service members in training accidents is low, but a panel of US lawmakers has called for the release of data to reveal the number of injuries and deaths from such incidents.
In 2015, the US Navy completed a major study on the dangers of special forces training in tandem with air accidents, resulting in the release of the data.
But no data for 2015 training accidents has been released.
Four American soldiers died in Nevada in late September when they were hit by a military vehicle.
There has been a significant increase in such incidents since 2000, says John Ross, author of the book College Prowlers.
Risks of training accidents have been on the rise, says John Ross, author of the book College Prowlers.
“They have come up despite the best intentions, and they have come up because as a result of the amount of training they have, and the troops who are in that training, there have been times when it hasn’t worked,” says Mr Ross.