China has complained to the United States about a stopover Taiwan leader Chen Shui-bian is planning to make in the U.S. state of California Monday.
China's state news agency, Xinhua, says Beijing has sent Washington a "solemn" message detailing its concerns.
Beijing considers Taiwan a part of its territory and objects to any country having relations with Taiwan officials, even in an informal capacity.
Mr. Chen is planning to stay overnight in the city of San Francisco before heading to Nicaragua Tuesday for the inauguration of President Daniel Ortega.
Last May, the United States turned down Taiwan's request for Mr. Chen to stop in San Francisco on his way to Costa Rica.
Some information for this report provided by AP and Reuters.