BEIJING/TOKYO — China condemned a visit by two Japanese ministers to a controversial shrine for war dead Thursday, further straining already tense relations between Asia's two largest economies. Sino-Japanese relations have soured sharply in the past month when a row over disputed islands led to violent anti-Japanese protests across China and badly hurt trade. The ministers' pilgrimage to the Yasukuni Shrine, seen by many in the region as a symbol of Japan's war-time militarism, came a day after a visit to the site by Japan's main opposition party leader and possible next prime minister, Shinzo Abe. China's official Xinhua news agency, meanwhile, said the Chinese navy would conduct a joint exercise on Friday in the East China Sea with the country's fishery administration and marine surveillance agency. It said the aim of the exercise was for “the effective maintenance of China's territorial sovereignty and maritime rights and interests”. Sino-Japanese relations deteriorated sharply in September after Japan bought the East China Sea islets that both Tokyo and Beijing claim, sparking anti-Japanese protests across China. Land minister Yuichiro Hata and Postal Service Privatization minister Mikio Shimoji were among a group of non-partisan lawmakers visiting the shrine during the autumn festival. Fourteen Japanese wartime leaders convicted as war criminals by an Allied tribunal are honored at the shrine along with other war dead. Hata said his visit was private. “I visited as a secretary general of the People's New Party. It won't be a big diplomatic problem,” said Shimoji, whose party is a small coalition partner of the ruling Democratic Party. China's Foreign Ministry disagreed. “The Yasukuni Shrine is a spiritual pillar used by Japanese militarism for its overseas aggression. It still enshrines Class A war criminals who owe victimized people heavy bloody debts,” spokesman Hong Lei said. — Reuters