An oil tanker east of Oman's Sohar was boarded by "armed unauthorized persons" in military uniforms on Thursday morning, according to the United Kingdom Maritime Trade Operations.

The Marshall Islands-flagged crude oil tanker was prosecuted in the past for carrying sanctioned Iranian oil, which was then confiscated by the U.S., an advisory note by British maritime security firm Ambrey said, adding that the tanker was headed in the direction of Bandar-e-Jask in Iran.

(With input from Reuters)