US President Joe Biden announced Friday that Nicholas Burns, a career diplomat who has served presidents of both political parties, is his pick for ambassador to China, ending months of speculations on who would take up the position after Terry Branstad left Beijing last October.

If confirmed by the Senate, Burns, former under secretary of state for political affairs, would become the 13th US ambassador to China.

Unlike Branstad, who had spent more than two decades at the helm of Iowa's state government and had little diplomatic experience before assuming the ambassadorial post, Burns has deep political ties and diplomatic experience, according to his biography.

He served as US ambassador to the North Atlantic Treaty Organization (2001-2005), during the presidency of George W. Bush, and as US ambassador to Greece (1997-2001) under President Bill Clinton, and was a spokesman of the State Department between 1995 and 1997.

He now teaches at Harvard University’s Kennedy School of Government.

The nomination of the crucial China posting came about three weeks after China posted its new ambassador to Washington on July 28.

Also on Friday, Biden announced his intention to nominate Rahm Emanuel as ambassador to Japan. Emanuel is a former mayor of Chicago and chief of staff to President Barack Obama.