Iran downed a US F-15E fighter jet, and a search-and-rescue operation is underway for the two-person crew, according to a US official.
The first known combat loss of a US fighter jet would mark a significant escalation in the five-week war that already has triggered a global energy crisis.
The New York Times, which reported earlier that a fighter jet was downed, said the fate of the crew was unclear.
The US Central Command and the White House didn't immediately respond to requests for comment.
Iran's semi-official Tasnim news agency carried a report Friday that claimed Iran had shot down a "highly advanced American fighter jet."
Iranian state media have made prior claims of shooting down American aircraft that were denied by the US. Central Command Thursday cited as false an Islamic Revolutionary Guard Corps claim that it had downed an enemy fighter jet over an island in the Strait of Hormuz.
"Iran's IRGC has made the same false claim at least half a dozen times," Central Command said in a social media post.
Iran targeted more sites in Arab Gulf states into Friday, hours after President Donald Trump issued fresh threats against Iranian infrastructure to pressure Tehran to start peace negotiations. The US president postedBloomberg Terminal a video of a bridge collapse to social media on Thursday, warning there would be "Much more to follow!" if Iran doesn't negotiate a deal.
Iran remained defiant, with Foreign Minister Abbas Araghchi saying strikes on civilian structures "will not compel Iranians to surrender." There's little sign that the country will relent on US demands to re-open the Strait of Hormuz and halt attacks, instead offering their own termsBloomberg Terminal for a deal.
Three tankers broadcasting Omani ownership appear to have navigated the Strait of Hormuz by hugging their home country's coastline, indicating a different route to a northerly path through Iranian waters.
Two oil supertankers, the Dhalkut and Habrut, and the liquefied natural gas vessel Sohar LNG headed east into the strait on Thursday, based on the satellite signals they were broadcasting. All three vessels are managed by Oman Ship Management Company, according to the Equasis marine database. The company couldn't be reached for comment.
While the Strait of Hormuz has been largely blocked since the start of the conflict, Iran has begun to negotiate transit for a handful of vessels tied to friendly nations, which have followed an agreed northerly route through its own waters. A container ship signaling French ownership recently used this path, in what appears to be the first known transit by a vessel linked to Western Europe since the Iran war all but shuttered the vital waterway.
On Thursday, Iran's state-run IRNA cited Deputy Foreign Minister Kazem Gharibabadi as saying that Tehran is drafting a protocol with Oman to monitor traffic through the Strait of Hormuz. Muscat's position on the comments was unclear.
The effective closure of the crucial channel has upended global energy markets, sending prices surging and putting growing international pressure on US President Donald Trump. Iran is also trying to set up a tolling system, seeking payments of as much as $2 million per voyage through the waterway.
The three ships transiting are particularly interesting because they are the largest type of oil tankers and the first LNG carrier to escape the gulf since the war began.
Each of the three vessels was broadcasting that they were Omani when transiting. They all stopped sending automated position signals at about 9:30 a.m. London time, when they were approaching, or just rounding, the tip of Oman's Mussandam Peninsula that juts northward into the strait.
The vessels reappeared on tracking monitors Friday, broadcasting positions off the coast of Muscat, Oman.
Tracking ships entering and exiting Hormuz has also been complicated by the intense signal jamming in the area, as well as signal spoofing.
The tankers are each hauling about 2 million barrels of crude, while the gas carrier appears to be empty, the tracking data show. One of the tankers loaded in Saudi Arabia in late February and was signaling its destination as Kyuakpyu in Myanmar, where a pipeline carries crude into western China. The other carrier is carrying crude from Abu Dhabi to an undisclosed destination.
The route followed by the three ships lies to the south of the designated shipping lanes through the waterway, shown in orange in the map, and far from the more northerly path that runs between Iran's Larak and Qeshm islands taken by most ships leaving the Persian Gulf in recent days, shown in yellow.
That northerly route has been associated with Iranian demands to approve and charge a fee for ships to transit the strait. But its shallower depth and tighter turns may make it unsuitable for the largest oil tankers.