A major Japanese oil tanker was damaged Monday in a chase by heavily-armed pirates off the coasts of Somalia and Yemen but no one was injured, officials and crew members said. The area is plagued by insecurity and considered to be among the most dangerous waterways for shipping in the world. The 150,000-tonne tanker Takayama, with a crew of 23, sustained damage but was able to sail on its own power after the attack at about 4:40 am local time (0140 GMT), its owner and operator Nippon Yusen Kaisha (NYK Line) said here. The attack occurred in international waters some 440 kilometres (275 miles) east of the Yemeni , Japanese officials said.