U.S.-China trade negotiations need to reach a successful end by March 1 or new tariffs will be imposed, U.S. Trade Representative Robert Lighthizer said on Sunday, clarifying there is a "hard deadline" after a week of seeming confusion among President Donald Trump and his advisers.

Global markets are jittery about a collision between the world's two largest economic powers over China's huge trade surplus with the United States and U.S. claims that China is stealing intellectual property and technology.

"As far as I am concerned it is a hard deadline. When I talk to the president of the United States he is not talking about going beyond March," Lighthizer said on the CBS show "Face the Nation," referring to President Donald Trump's recent decision to delay new tariffs while talks proceed.