Eleven Iranian boats spent an hour making “dangerous and harassing approaches” of six U.S. Navy vessels near Iran’s coast on Wednesday, according to the U.S. military. 

Iran and the United States came close to war last summer after months of tensions in the Persian Gulf. The two countries have more recently moved their confrontations to neighboring Iraq, where U.S. forces are deployed close to Iranian proxies. But the latest incident could be a sign of more direct confrontations to come. 

“Iranian sources told Al-Jazeera that the maneuver near an American ship was in response to a recent attempt by an American fighter [jet] to violate Iran’s airspace,” Iran’s state-run Fars News Agency claimed on Thursday. “The American fighter recently tried to enter Iran’s airspace, but an alert by Iran’s air defense changed the fighter’s direction.” 

Al-Jazeera, a television station based in nearby Qatar, reported in Arabic that an American fighter had attempted to penetrate Iranian airspace before turning back several days ago. It was unclear why Iran’s own state-run news agency would cite its Qatari counterpart rather than quote Iranian sources directly. 

“While U.S. aircraft routinely operate in international airspace throughout the U.S. Central Command area of responsibility and that international airspace is often in the vicinity of Iran, no U.S. aircraft have attempted to enter Iranian airspace recently,” Central Command spokesperson Capt. Bill Urban told the National Interest on Friday.

Wednesday’s incident began when several Islamic Revolutionary Guards Corps speedboats “repeatedly crossed the bows and sterns of the U.S. vessels at extremely close range and high speeds,” including one approach at only ten yards, according to a statement by the U.S. Naval Forces Central Command. 

The Iranian boats approached USS Lewis B. Puller, USS Paul Hamilton. USS Firebolt, USS Sirocco, USCGC Wrangell and USCGC Maui, which were conducting “joint integration operations” with Army helicopters in international waters, according to the statement. 

“The U.S. crews issued multiple warnings via bridge-to-bridge radio, five short blasts from the ships' horns and long range acoustic noise maker devices, but received no response,” the Navy stated. “After approximately one hour, the [Islamic Revolutionary Guard Corps Navy] vessels responded to the bridge-to-bridge radio queries, then maneuvered away from the U.S. ships and opened distance between them.” 

Iran did not contest the U.S. military’s version of events. Fars News Agency shared footage published by the U.S. Navy in its report. 

The Iranian maneuvers “increased the risk of miscalculation and collision,” violated “internationally recognized maritime customs, and were not in accordance with the obligation under international law to act with due regard for the safety of other vessels in the area,” the Navy claimed. 

U.S. Secretary of State Mike Pompeo declined to comment on the details of the incident in a Fox News interview on Thursday. 

‘We have seen this before, where the Iranians behaved in ways that were inconsistent with international law,” he said. “I think the American people know that President Trump is serious about protecting Americans, protecting our military, protecting our Navy. I am very confident that we’ll make decisions that do that.” 

Matthew Petti is a national security reporter at the National Interest. Follow him on Twitter: @matthew_petti. 

This article has been updated to reflect the U.S. Central Command's response to the National Interest's request for comment.

Image: Flickr / U.S. Department of Defense