A fleet of drones has allowed Iran to watch every U.S. ship in the Persian Gulf region and develop an archive of their daily movements, Iran’s top naval commander said in an interview published Tuesday.

The comments come days after President Trump said that a U.S. warship destroyed an Iranian drone. Iran denied that a drone was shot down and subsequently released a video of a U.S. ship — video that Tehran claimed, without explanation, proved its version of events.

In an interview with an Iranian news site, Rear Adm. Hossein Khanzadi, the head of Iran’s navy, expanded upon this point, claiming that every U.S. ship in the region was watched by drones.

“Our drones have significant ranges and have no limitations in communication links. We have a complete archive of images of American vessels approaching from very far distances,” Khanzadi told the Young Journalists Club.

Khanzadi added that there was “an immense archive of the day-to-day and even moment-to-moment movements of American forces, whether in the Persian Gulf” or the Gulf of Oman.

In a statement in response to questions about the Iranian claims, the U.S. Central Command, which oversees military activities in the Middle East, said it does not comment on matters of intelligence but remained “postured and prepared with forces that span the full range of combat capability.”

Iran has recently bragged about technological advances in its drone program and promoted videos with dozens of drones on staged bombing runs. However, Khanzadi’s remarks were greeted with skepticism by some analysts, who say that Iran has often inflated its capabilities in a bid to rally domestic support and confuse foreign rivals.

“There’s more than an element of bravura in the claim” that Iran can watch all U.S. ships in the region, said Douglas Barrie, a senior fellow specializing in aerospace at the International Institute for Strategic Studies in London.

Jeremy Binnie, Middle East and North Africa editor at Jane’s Defense Weekly, said there was little doubt that Iran could track ships going through the Strait of Hormuz, a narrow waterway through which a significant amount of the world’s traded oil is moved.

“Their ability to track all those ships once they are in the gulf is far more questionable,” he added.

Khanzadi’s comments highlight the central role that unmanned aerial vehicles are playing in the dispute over the Persian Gulf. Last month, Iran shot down a U.S. drone that it said had entered its airspace. The United States planned a retaliatory attack, but Trump called it off at the last minute. 

Trump said Thursday that a U.S. Navy ship destroyed an Iranian drone that came too close to it. The drone came within 1,000 yards of the USS Boxer in the Strait of Hormuz before the crew “took defensive action” and “immediately destroyed” it, according to the president.

The next day, Iran rejected the claim and said that all of its drones had returned to their bases. “We have not lost any drone in the Strait of Hormuz nor anywhere else,” tweeted Deputy Foreign Minister Abbas Araghchi.

Iran’s Islamic Revolutionary Guard Corps later released video apparently shot from a drone tracking the USS Boxer. The drone recorded three hours of video of the ship and five other vessels from when they entered the Strait of Hormuz, the Revolutionary Guard said on its website.

Although it was not clear how the video proved that a drone had not been shot down, it did offer a glimpse into how Iran uses the unmanned vehicles to track U.S. ships.

Since the United States pulled out of a nuclear agreement between Iran and world powers and reimposed sanctions last year, tensions have been running high with Tehran. Last week, Iranian forces seized at least one British tanker that Tehran said had entered its territorial waters illegally.

Although Iran uses its drones primarily for surveillance, U.S. officials and experts have expressed concern that the aerial vehicles could be fitted with weapons and used in combat by Tehran and its allies. 

Iran’s semiofficial Tasnim News Agency suggested Tuesday that American military leaders were worried about risks posed by the drone technology.

“Pentagon generals are deeply concerned that if Iranian drones can pass their radars without being tracked by their terminating mechanisms, they might as well carry out military attacks on their vessels if needed,” the article said.

Britain is expected to meet with Iran, along with all other parties to the nuclear deal except the United States, in Vienna on Sunday, the European Union’s foreign policy unit announced Tuesday.

Iranian Foreign Minister Mohammad Javad Zarif tweeted congratulations Tuesday to Britain’s new prime minister, Boris Johnson, who has been chosen to succeed Theresa May. He also offered a warning.

“Iran does not seek confrontation. But we have 1,500 miles of Persian Gulf coastline,” Zarif wrote. “These are our waters & we will protect them.”