Japan has called for calm in the wake of China's apparent decision to suspend top-level ties over a territorial row. A government spokesman said Japan had not yet been formally informed of the move but urged China to act prudently. Yesterday Chinese media said ministerial and provincial-level contacts had been suspended. It followed Japan's decision to extend the detention of the captain of a Chinese trawler accused of hitting two Japanese vessels in waters both claim. Japan has a further 10 days to either charge or release the captain. The fishing boat's 14 Chinese crew were released last week. The incident on 7 September happened near uninhabited islands known as Senkaku in Japan and Diaoyu in China. Meanwhile, a planned visit by 1,000 Japanese students to the Shanghai Expo has already been called off. The students were scheduled to depart tomorrow but, late yesterday China told the Japanese embassy in Beijing that they should not come. Japan described the move as extremely inappropriate.