The new US ambassador to China, Nicholas Burns, has arrived in the country and will be in quarantine for three weeks, the US embassy said in a tweet on Saturday.
The United States has been without an ambassador in Beijing since Terry Branstad stepped down in October 2020.
Burns, a veteran diplomat and former US ambassador to NATO, arrives at a time when relations between the world's two biggest economies are at their worst in decades.
Recent points of friction include the US-led diplomatic boycott of last month's Beijing Winter Olympics, and China's diplomatic backing of Russia in its invasion of Ukraine.
The embassy tweet said Burns' travel plans had been delayed due to the pandemic and that a group of US mission personnel and their families travelled with him.
President Joe Biden's nomination of Burns for the post was approved by the US Senate on 16 December.