Armed men boarded a ship off the coast of Iran near the crucial Strait of Hormuz, a U.K. monitoring organization said Tuesday, without elaborating.
The incident near Iran’s Ras al-Kuh coast was not immediately acknowledged by either the U.S. Navy’s Bahrain-based 5th Fleet, nor Iranian officials. However, it comes after a private maritime intelligence firm warned of suspicious incidents in recent days near the strait, through which a fifth of all oil is traded.
It also comes amid months of heightened tensions between Iran and the U.S., which has seen attacks on shipping, as well as oil tankers seized.
The United Kingdom Maritime Trade Organization said in an alert Tuesday night the vessel “had been boarded by armed men while at anchor” near the strait off the Iranian coast.
“All vessels in the vicinity are to stay vigilant and to report any incidents,” the warning said, urging ships to “exercise caution.”
The 5th Fleet did not immediately respond to a request for comment.
Dryad Global, the private maritime intelligence firm that issued the first warnings about suspicious incidents, identified the ship as a “Hong Kong-flagged vessel,” without elaborating. It said the 22 crew members aboard were all Chinese. It did not say how it knew the information.