WASHINGTON, Feb 18: Japan will formally join the United States this weekend in declaring the Taiwan Strait a common security concern in a move likely to anger China, the Washington Post said on Friday.

The Post said a formal agreement would be announced after US Secretary of State Condoleezza Rice and Defence Secretary Donald Rumsfeld meet their Japanese counterparts here on Saturday.

"This is the first time that Japan has made its stance clear," Koh Se-kai, Taiwan's special representative to Japan, told the Post, which called the move the biggest change in the US-Japanese security alliance since 1996.

"In the past, Japan has been very indirect on the Taiwan issue," Mr Koh was quoted as saying. "We're relieved that Japan has become more assertive." The State Department would not confirm the move by Japan, which ended its diplomatic ties with Taiwan in 1972 to establish relations with China.

Secretary of State Condoleezza Rice side stepped a question on the reported agreement and said only that the US and Japanese ministers would discuss "how we continue to promote peace and security in this region".

"We and the Japanese, of course, enjoy very deep and broad relations in an alliance to try to both bring and maintain peace and stability in the Asia-Pacific region," Ms Rice said.

She told reporters after talks with her Dutch counterpart Bernard Bot that Washingtion and its allies were determined "that the cross-strait problem would be resolved peacefully" without unilateral moves by either China or Taiwan. Japanese Defence Agency chief Yoshinori Ono said the two countries would "fully discuss destabilizing factors". -AFP