Stolt Tankers said its vessel the Stolt Apal was attacked by pirates 75 nautical miles off Yemen's coast on Sunday.
Stolt Tankers said six armed pirates approached the vessel in two speedboats.
"After multiple warning shots were fired by the armed guard team aboard Stolt Apal, the skiffs opened fire on the ship. The armed guard team returned fire, disabling one skiff and ending the pursuit," Stolt Tankers said."The bridge area sustained minor damage from bullets but there were no injuries, no pollution and no cargo impacted on Stolt Apal. A coalition warship responded and Stolt Apal has resumed her voyage." Earlier on Sunday, the United Kingdom Maritime Trade Operations (UKMTO) reported a vessel was attacked in the Gulf of Aden offshore of Yemen's port of Mukalla, without giving further details.
"Vessels transiting the area are advised to exercise extreme caution," UKMTO said in a warning notice on its website. The attack happened at 1230 GMT, it said.