Yemeni special forces on Monday freed a Yemeni oil tanker seized by Somali pirates in the Gulf of Aden, killing three pirates and capturing at least nine on board, a government official said. The ship, named Qana, was seized by Somali pirates off Yemen's coast on Sunday but was empty of oil cargo. The deaths on Monday took to five the number of pirates killed as Yemeni forces battled for two days to take back the vessel, Reuters reported. They were escorting the tanker to the Yemeni port of Aden on the southern tip of the Arabian Peninsula. Yemen, across the Gulf of Aden from Somalia, is a small producer of oil and exports 200,000 barrels per day but is one of the world's poorest countries. The tanker, with a 23-strong crew of which three are Indian and the rest Yemenis, has a capacity of 3,000 tonnes but was not carrying any cargo when it was seized. The pirates had briefly seized three other vessels earlier before Yemeni forces freed them, a Yemeni official said.