KHUZESTAN PROVINCE — A U.S. F-15E Strike Eagle fighter aircraft was shot down over Iran on Friday, and U.S. forces were searching for one of the two crew members who remained missing. The pilot was rescued and taken out of the country for medical treatment, but the second crew member had not been located as the search continued in hostile territory.

Iran's Islamic Revolutionary Guard Corps claimed it shot down the F-15E, the first time a U.S. aircraft had gone down inside Iran during the conflict, which began on Feb. 28. Both crew members were wounded and managed to escape Iranian airspace before the aircraft went down. The search-and-rescue mission came under Iranian fire, with multiple U.S. aircraft struck during the operation.

A U.S. aircraft supporting the rescue mission was hit by Iranian fire, a U.S. official said. A single-pilot A-10 Thunderbolt supporting the operation made it to Kuwaiti airspace, where the pilot ejected safely and the aircraft crashed in Kuwait, the official said. Two U.S. military Black Hawk helicopters involved in the search-and-rescue efforts were also struck by Iranian fire, though the service members on board were unharmed, the official said.

Video from Iran showed U.S. military helicopters and at least one refueling aircraft operating over Khuzestan province. The IRGC launched a search for the missing American using troops and local residents and offered a reward of approximately $66,000 to capture the crew member alive. Regional officials in Kohgiluyeh and Boyer-Ahmad province asked locals to find those on board the downed jet and offered a reward, while a representative of merchants and businesses in the province offered approximately $60,000 for the capture of the aircrew.

The governor of Kohgiluyeh and Boyer-Ahmad province denied that the second American crew member had been captured and arrested. The regional leadership of the IRGC also denied that the second crew member had been captured and detained by special airborne forces.

President Donald Trump's national security team spent much of Thursday in the West Wing briefing him on the search-and-rescue mission. Asked whether the downing would affect negotiations with Tehran to end the war, Trump said, "No, not at all. No, it's war." He said the United States had been negotiating with Iran to end the conflict, though Iran said no direct negotiations with the U.S. were taking place.

In recent days, the U.S. had increased the number of bombing runs over Iran.

Jonathan Hackett, a former U.S. Marine Corps Special Operations specialist, said a rescue team's priority would be to look for signs of life. A former pararescue squadron commander said combat search-and-rescue missions may involve at least 24 pararescue jumpers operating from Black Hawk helicopters. The jumpers are trained to deliver medical aid, evade enemy forces, and reach a location where they can be rescued.