Naval personnel have been trained to use a remotely piloted underwater vehicle, commonly known as a drone, to carry out covert operations.
On Sunday, the Israeli military killed a Navy Seal who was working at a nuclear-powered submarine base in the Gaza Strip.
“This is the first time that the Navy SEAL was killed by a drone strike,” the Pentagon said in a statement.
The drone attack took place at the Israeli naval base in Ashkelon, the statement added.
“The Navy Seal was on a training mission in a remote area of the Ashkelons coastal plain when he was attacked by a remotely operated underwater vehicle,” the statement said.
In the past, the Navy Seal had worked as a marine security officer in a training area in the area, the Pentagon added.
Last week, the US Navy launched an unmanned underwater vehicle (UUV) strike against an Iranian nuclear facility in the Qom Strait.
In March, the USS Vincennes struck an ISIS command center in the Syria-Iraq border region, killing five militants, including three senior commanders.
The Vincenne fired a Hellfire missile at the compound, which the Pentagon has said was an ISIS training center.
Last month, a U.S. Navy SEAL killed three Iranian sailors after the two sides exchanged fire in the Persian Gulf.
U.S.-led coalition forces have carried out more than 3,000 drone strikes in Iraq and Syria since the beginning of 2016, according to data from the Bureau of Investigative Journalism.
This article was updated at 7:07 p.m.
ET to include additional details on the killing of the Israeli soldier.