Another American service member has died in the war with Iran, the Pentagon said on Sunday, bringing the number of American troops killed in the conflict to seven.

The service member, who was not publicly identified while the military notifies relatives, was seriously injured on March 1 when Iran struck a Saudi military base where American troops were stationed, U.S. Central Command said in a statement. The service member died from those injuries while military health officials were preparing a transfer for more advanced medical care at an U.S. military hospital in Germany, officials said.

On Saturday, President Trump witnessed the return of the bodies of the first six Americans killed in the war in a solemn ceremony at Dover Air Force Base in Delaware. The six Army Reservists were killed after an Iranian drone strike Sunday at Shuaiba port in Kuwait.

Since the war began on Feb. 28, Iranian retaliatory strikes have killed at least 20 people, which, along with the American troops, includes people killed in Israel and in other countries in the region. Iran has borne the brunt of the death toll of U.S. and Israeli strikes. Earlier last week, the Red Crescent Society said nearly 800 people had been killed in Iran, but it has not provided an official update to that figure in recent days. On Friday, Iran’s ambassador to the United Nations put the number of dead at over 1,300.

For the United States, the grim toll in the first week of the war signaled that Iran was more prepared for war than the Trump administration anticipated, U.S. military officials said. Iran has continued to put up a fight, even after its supreme leader, Ayatollah Ali Khamenei, and other top officials were killed in Israeli attacks with intelligence help from the C.I.A.

In the past, Iran has given warning before launching retaliatory strikes and made known which bases housing U.S. troops it intended to hit. But since the start of the war, its strikes have been widespread and less predictable.

Mr. Trump and other administration officials said multiple times last week that they expect more U.S. casualties.

Pentagon Announces Seventh U.S. Death in War With Iran