Iran has severely damaged several American military bases in the Middle East, officials say.

There are several ways the United States could attempt to reopen the waterway, all of which carry substantial risks.

The crash was not because of hostile or friendly fire, U.S. Central Command said. Four crew members died, it said, bringing the number of U.S. service members killed in the Iran conflict to at least 11.

Eight Americans have been seriously wounded, military officials said, but the bulk of the injured have already returned to duty. Seven Americans have been killed.

The service member killed was not publicly identified, but U.S. Central Command said the death was caused by injuries after an attack on a Saudi military base.

NATO downed a missile fired by Iran at Turkey, and a U.S. sub sank an Iranian Navy ship off Sri Lanka, thousands of miles from the war zone.