China expert Joseph Donovan will be appointed deputy chief of mission to the U.S. Embassy to Japan, replacing Michael Michalak, U.S. administration and diplomatic sources said Wednesday.

The appointment of Donovan, director of the Chinese and Mongolian Affairs Office at the State Department, is to assist new Ambassador to Japan Thomas Schieffer, who has little experience in Japanese and other Asian affairs, the sources said.

Donovan had previously served in Beijing and Tokyo.

The sources said Donovban's background in China affairs will help the embassy deal with bilateral ties, given Beijing's growing economic and military presence in the Asia-Pacific region.

Career diplomat Donovan, who is also currently acting deputy assistant secretary of state for East Asian and Pacific affairs, was one of the key players in the recent U.S.-Chinese agreement on their first regular high-level dialogue on economic and political issues.

Schieffer, who arrived in Tokyo earlier this month to take up his duties, is a longtime Texas friend of President George W. Bush and is believed to be one of the closest people to the president.