Taiwan President Chen Shui-bian, in a move likely to anger China, admitted on Friday that his government alerted Tokyo about the recent intrusion into Japanese waters of a Chinese submarine. "It was an honour that Taiwan could provide related information beforehand to Japan and the United States, and later this information was proved correct," Chen said. He spoke while receiving Hatori Rejiro, chairman of Japan's Interchange Association which handles ties with Taiwan, who is in Taipei to attend a trade conference. "We believe that we all feel a threat coming from China. So how to safeguard peace and stability is in the Asia-Pacific is in the common interests of Japan, the U.S. and Taiwan," Chen added. A foreign nuclear submarine intruded into Japanese waters between the Japanese island of Okinawa and Taiwan last Wednesday, but left two hours later after being chased by Japanese warships. Japan suspected it was a Chinese sub and protested to China last Friday. On Tuesday, Japan said China had apologized that its submarine had "erroneously entered Japanese waters for technical reasons." Taiwan and Japan have maintained close trade ties since 1972 when Japan switched diplomatic recognition from Taipei to Beijing. Taipei and Tokyo also maintain an ambiguous military coalition because Taiwan was a Japanese colony between 1895-1945 and because the Japan-U.S. Security treaty also covers maintaining peace and stability in Japan's surrounding regions. Last month Taiwan voiced support for Japan's becoming a permanent member of the U.N. Security Council, apparently in exchange for Japan's support Taiwan efforts to rejoin the World Health Organization (WHO).