The United States is pushing for regular reviews of China's progress on pledged trade reforms as a condition for a trade deal — and could again resort to tariffs if it deems Beijing has violated the agreement, according to sources briefed on negotiations to end the trade war between the two nations.

A continuing threat of tariffs hanging over commerce between the world's two largest economies would mean a deal would not end the risk of investing in businesses or assets that have been affected by the trade war.

"The threat of tariffs is not going away, even if there is a deal," said one of three sources briefed on the talks who spoke on condition of anonymity.