THE diplomatic tug-of-war between Beijing and Taipei deepened yesterday as mainland leaders stepped up their offensive to lure the island's foreign supporters. Meanwhile, Taiwan said it was investigating claims that its military had beaten up Chinese fishermen. Increasing the pressure was President Jiang Zemin, just returned from New York for the United Nation's 50th anniversary where he repeatedly stressed the 'one-China' argument. Mr Jiang met Kyrgyzstan Prime Minister Apas Jumagulov in Shanghai yesterday and again raised the Taiwan issue in their discussions. Instead of flying back directly from New York, Mr Jiang took a detour and stopped over at Anchorage, Alaska - almost the same route taken by Taiwan President Lee Teng-hui when he made his ground-breaking visit to the US in June. Mr Jiang was greeted at Anchorage Airport by Deputy Governor Fran Ulmer and Mayor Rick Nystrom and 'had a friendly conversation' with them, Xinhua (the New China News Agency) said. The official media yesterday also reported remarks by Foreign Minister Qian Qichen in New York that the Taiwan issue remained a central issue in Sino-US ties. Meanwhile, Vice-Premier Li Lanqing departed for Africa on a three-week goodwill visit aimed at cementing political ties with states such as Mali, Guinea, Senegal, Gabon, Cameroon and the Ivory Coast. It is believed Mr Li will try to persuade the countries to stick to the one-China policy by promising more trade. Taiwan has been lobbying small African countries for recognition and support for its bid to rejoin the UN. Separately, Taiwan said yesterday it was investigating an accusation by China that its military had beaten up mainland fishermen. 'We have asked the Defence Ministry to investigate these incidents,' said Kao Koong-lian, acting chairman of the Mainland Affairs Council. He was referring to a letter from Beijing's Association for Relations Across the Taiwan Strait, which demanded the release of the fishermen. It accused Taiwan troops stationed on the island of Quemoy, off the coast of Fujian, of repeatedly intercepting Chinese fishing boats, beating fishermen and destroying their gear.