WASHINGTON — The United States and China have agreed to double the number of airline flights that each other's airlines can operate between the countries, from four to eight per week.

The deal marks a further easing of a standoff between the world's two biggest economies over travel restrictions imposed during the pandemic.

The U.S. Transportation Department announced the increase Tuesday, saying that China's aviation authority decided this week to permit expanded flights by United and Delta.

Shortly after the announcement, Chicago-based United Airlines said it will go from two to four flights per week between San Francisco and Shanghai via Seoul, starting Sept. 4. 

The Transportation Department said Atlanta-based Delta Air Lines is also eligible to increase its two weekly flights to four. Delta did not comment immediately.

Chinese airlines that already fly to the United States — Air China, China Eastern Airlines, China Southern Airlines and Xiamen Airlines — will be allowed to make eight weekly round-trips instead of four, the department said.

The Transportation Department repeated its hope that China will agree to fully restore the treaty rights of U.S. airlines to serve China, but called the most recent increase in flying "a step in the right direction."

In early January, there were more than 300 flights per week between the two countries, but that number nosedived after the pandemic undercut demand for international air travel. United, Delta and American Airlines suspended flights to China by mid-March.