BEIJING (Reuters/AFP) - China on Saturday denounced a visit by two Japanese local lawmakers to disputed islands in the East China Sea at the heart of a territorial row between the two Asian powers. The chain of isles, known as Diaoyu in China and Senkaku in Japan, has been an integral part of China since ancient times, Chinese Foreign Ministry spokeswoman Jiang Yu said in a statement. The misdeed by the two local Japanese representatives violates Chinas territorial integrity, she said in the statement on the ministrys website. China has made a solemn representation and a strong protest to Japan. The lawmakers, who went to the islands by boat on Friday, are members of the Ishigaki city council in Okinawa, Japanese broadcaster Fuji TV said. Ishigaki city is, according to Japan, responsible for the administration of the uninhabited isles. Japans policy is not to allow anyone to land on the islands, Chief Cabinet Secretary Yoshito Sengoku told reporters on Friday, adding that the coast guard was looking into it. Ties between Asias two biggest economies chilled in September after a Chinese fishing trawler collided with Japanese patrol vessels near the isles, which are close to potentially vast oil and gas reserves. Meanwhile, Japan plans to deploy advanced interceptor missiles at its air bases across the nation to counter the threat of North Koreas ballistic missiles, Kyodo News reported on Saturday. The deployment of Patriot Advanced Capability-3 interceptor missiles will be under new five-year defence policy guidelines to be announced as early as next week, Kyodo said, quoting government and defence officials. The PAC-3 missile system, designed to shoot down an incoming missile from the ground, will be deployed to all six of the Air Self-Defense Forces air defense missile groups from three at present, Kyodo said. The move comes amid heightened tensions on the Korean Peninsula following North Koreas artillery attack on a South Korean island last month, and Chinas rapid military build-up and increasing naval activity. On Friday, Japan and the United States finished their biggest-ever joint military exercise in a powerful display of firepower after a US and South Korean show of force to pressure Pyongyang. The new guidelines will also stipulate equipping all six Aegis destroyers with Standard Missile-3 interceptors, while increasing the number of submarines from 16 to 22 for enhanced vigilance in southwestern Japan. The number of escort ships will be increased from 47 to 48 while the number of major operational aircraft will be trimmed from 350 to 340 due in part to the larger size of transport planes.