DUBAI, United Arab Emirates (AP) — Attackers firing machine guns and rocket-propelled grenades boarded a ship off the coast of Somalia on Thursday, British officials said.

The British military’s United Kingdom Maritime Trade Operations center issued an alert over the attack, warning ships in the area.

The private security firm Ambrey also reported that an attack was underway, saying it targeted a Malta-flagged tanker. Ambrey added that it appeared to be an assault by Somali pirates, who have been reported as operating in the area in recent days.