Yemeni coast guard forces have freed a hijacked Yemeni oil tanker and arrested 11 Somali pirates, the first time the country has successfully retaken a seized vessel, officials said Monday, AP reported. The coast guard exchanged gunfire with the pirates and took control of the oil tanker Qana on Sunday, a security official said. The vessel had been hijacked earlier in the day while heading between the two southern Yemeni ports of Mukalla and Aden. The security official spoke on condition of anonymity because he was not authorized to speak to the press. A strengthened international naval force has been patrolling the waters since the beginning of this year Pirates have hijacked more than 100 ships off the Somali coast over the last year, including one in a dramatic standoff between pirates and the U.S. Navy earlier this month. The Gulf of Aden is one of the world's busiest shipping lanes. The Yemeni oil tanker seized Sunday was not carrying any crude at the time of the attack, said the head of the company that owns the vessel, Mohammed Abdul-Rahman.