North Korea's Air Koryo flying to Shanghai twice weekly

July 12 (UPI) -- North Korea's national carrier has resumed flights between Pyongyang and China's largest city, a sign the two countries are resuming exchange ahead of any significant breakthrough on North Korea denuclearization.

A plane belonging to Air Koryo was seen at Shanghai's Pudong Airport on Thursday, South Korean news network Channel A reported.

The network's analysis of flight data revealed Air Koryo was traveling to Shanghai every three days, and the flights may have begun in July.

The flight leaves Pyongyang for Shanghai every Thursday and Sunday, then returns to Pyongyang every Friday and Monday.

The flight data was confirmed by a source at the Korea Trade-Investment Promotion Agency, a South Korean government body.

The development confirms an earlier report in June that China agreed to open international routes to Pyongyang, connecting the city to Beijing, Shenyang, Shanghai and Chengdu.

Plans to create routes to North Korea from Chengdu and Xian have been suspended owing to U.S. pressure, according to Channel A.

North Korean flights to and from Shanghai were suspended in August 2017, when tensions escalated following North Korea's test of a long-range missile.

Tickets are only available offline, according to Channel A.

North Korea's economic recovery depends heavily on Chinese cooperation.

Yonhap reported Thursday Ri Su Yong, vice chairman of the ruling Workers' Party's Central Committee, was briefly in Beijing and could have made contact with the Chinese.

Chinese Communist Party foreign liaison vehicles were seen at the airport around the time of his arrival, according to the report.