With the Iran war now reaching about a month, U.S. Central Command said the count of Americans wounded has moved past 300 as additional Marine forces begin arriving in the region. The latest update followed a Friday strike on Saudi Arabia’s Prince Sultan air base that left at least 15 U.S. troops injured, including five described as seriously hurt, according to people briefed on the matter who spoke on condition of anonymity because they were not authorized to discuss details publicly.

The base, about 96 kilometers (60 miles) from Riyadh, is operated by the Royal Saudi Air Force but also used by U.S. troops. The Friday attack came as the base had also been targeted earlier in the week, including one incident in which 14 U.S. troops were injured and another where no one was hurt but a U.S. aircraft was damaged, the people briefed said.

The people briefed said Iran fired six ballistic missiles and 29 drones at the Prince Sultan air base. U.S. officials initially reported that at least 10 U.S. troops were injured, including two seriously wounded, before the later briefing raised the figures.

Beyond the Saudi base incident, Central Command said more Marines were already reaching the Middle East. U.S. Central Command said Saturday that the USS Tripoli, an amphibious assault ship, has arrived carrying about 2,500 Marines. Central Command said the ship and elements of the 31st Marine Expeditionary Unit are based in Japan and that they were conducting exercises around Taiwan when the deployment order came almost two weeks earlier.

Central Command said the USS Tripoli also brings transport and strike fighter aircraft as well as amphibious assault assets to the region. It said the USS Boxer and two other ships, along with another Marine Expeditionary Unit, have also been ordered to the region from San Diego.

Before the arrival of the Marines, the U.S. military had already built up what Central Command described as the largest American force in the region in more than 20 years, including two aircraft carriers, several other warships and about 50,000 troops. Central Command said the USS Gerald R. Ford, the newest U.S. aircraft carrier, recently left the Middle East for repairs and supplies in Europe after a fire in a laundry room affected some sleeping quarters aboard ship.

The casualty figures that have driven the force build-up include both battlefield injuries and deaths tied to earlier incidents. U.S. Army Sgt. Benjamin N. Pennington, 26, was wounded during a March 1 attack on the base and later died, the report said. The report said 13 service members have been killed in the war so far, including six who died when an Iranian drone struck an operations center at a civilian port in Kuwait and six who died when their refueling plane crashed in Iraq after an incident involving another aircraft that the U.S. military said was “not due to hostile or friendly fire.”

Central Command said Friday that more than 300 service members had been wounded in the war, with most returning to duty, while 30 remained out of action and 10 were considered seriously wounded. The Pentagon did not immediately respond to an email seeking comment Saturday on the U.S. casualties at the Saudi base.

U.S. officials and regional assessments tied the broader war to disruptions beyond military targets. The report said the conflict has upended global air travel, disrupted oil exports and pushed fuel prices higher, with Iran’s grip on the Strait of Hormuz exacerbating the economic fallout.

President Donald Trump has said the United States wants to end Iran’s control of the strait, and he told Americans on the timeline for renewed pressure. The report said Trump gave Tehran until April 6 to reopen the strait, while Iran has said it has not engaged in negotiations.

In remarks Friday, Secretary of State Marco Rubio said the United States can meet its objectives “without any ground troops,” while also warning that Trump “has to be prepared for multiple contingencies.” Rubio said American forces are available “to give the president maximum optionality and maximum, opportunity to adjust to contingencies should they emerge,” the report said.

James F. Jeffrey, a scholar at The Washington Institute for Near East Policy who previously served as deputy national security adviser under President George W. Bush, said the relatively low number of American deaths and injuries pointed to U.S. operational choices. “It’s amazing how low the casualties have been, given the amount of stuff that the Iranians have fired,” Jeffrey said, according to the report.

Jeffrey said the Islamic Republic’s goals were not primarily killing Americans, arguing that Iran’s strategy focused on economic pain for U.S. allies and the broader world. “We have not stopped Iran from its campaign against the Gulf,” he said, according to the report, adding that Iran had not eliminated all missiles and that it still has “the 400-plus kilograms of highly enriched uranium.”