A Yemeni security official says coast guard forces have freed a hijacked Yemeni oil tanker and arrested 11 pirates. The official said on Monday that the coast guard exchanged gunfire with the pirates and took control of the oil tanker Qana. The vessel was hijacked Sunday while heading between two southern Yemeni ports. The official spoke on condition of anonymity because he was not authorized to speak to the press. Mohammed Abdul-Rahman, the head of the company that owns the ship, said the tanker was among four other vessels being escorted by a Yemeni coast guard boat. The three other vessels escaped the attack. The hijacked tanker was not carrying any oil at the time. Pirate attacks have surged off Somalia over the past year.