President-elect Donald Trump has offered the post of U.S. ambassador to China to Iowa Gov. Terry Branstad, a longtime friend of Chinese President Xi Jinping, according to three people close to the matter.

Branstad, a Republican, has accepted the offer, said the three people, who asked for anonymity.

The decision comes at a time of heightened tensions with China after Trump abandoned almost four decades of diplomatic protocol on Dec. 2 by speaking directly with the leader of Taiwan, which Beijing considers a rogue province. Trump has been critical of China's currency policies and military build-up.