The incident occurred off the Yemeni port city of al-Mukalla.
"Military authorities have reported that the vessel was boarded by unauthorized personnel while transiting eastward in the Gulf of Aden," writes UKMTO.
It is unclear who is behind it and whether there are any links to the unrest in the Middle East. Iran has recently asked its allies, the Houthi movement in Yemen, to prepare to close the strategic Bab al-Mandab Strait if the United States attacks Iranian energy infrastructure. The strait is the southern gateway to the Red Sea and a vital shipping route for global trade.
According to Reuters, it is a chemical tanker. The attackers are said to be armed and have taken control of the ship, which was heading for the port city of Bosaso in northern Somalia.
