WASHINGTON (REUTERS) - China and the United States will each allow air carriers to double current flights to eight per week between the world's two largest economies, the US Transportation Department said on Tuesday (Aug 18).

The department said it will allow four Chinese passenger airlines currently flying to the United States to double flights to eight weekly round-trips, as China has agreed to allow US carriers to double flights to China.

US carriers voluntary halted flights to China after the coronavirus outbreak. President Donald Trump on Jan 31 barred nearly all non-US citizens from travelling to the United States from China.

United Airlines said on Tuesday it will increase flights to China to four flights per week from San Francisco to Shanghai starting Sept 4, while the department said Delta Air Lines was also eligible to go from two-times weekly to four-times weekly.

Delta is also going to four flights after it said in June it would operate flights to Shanghai from Seattle and Detroit beginning in July, all via Seoul. On Tuesday, Delta it would add one weekly flight from Detroit and Seattle each to Shanghai, via Seoul, beginning Aug 24.

The US government still hopes China will agree to restore full US flight rights under their bilateral aviation agreement, the Transportation Department has said, adding as China allows additional flights it will respond in kind.

The US-China agreement allows both countries to operate more than 100 weekly flights between the two nations.

The United States had threatened to bar Chinese passenger flights in June after Beijing did not immediately agree to restore flights by US airlines.

In May, the Trump administration said Air China, China Eastern Airlines Corp, China Southern Airlines Co, Hainan Airlines Holding Co and their subsidiaries had to file schedules.

Chinese authorities previously agreed to some changes on requirements for US carriers, including allowing temperature checks to be done before flights take off for China, rather than mid-flight as previously discussed, Reuters reported in June.