China, facing criticism that it is not doing enough to pressure North Korea to drop its nuclear program, said Monday that the root cause of North Korean missile launches is Pyongyang’s friction with the United States and South Korea.

North Korea fired a banned ballistic missile on Sunday, its first test since U.S. President Donald Trump took office. The missile, launched as Trump hosted Japanese Prime Minister Shinzo Abe in Florida, is believed to have flown about 500 kilometers (300 miles) before splashing down in international waters.

Foreign Ministry spokesman Geng Shuang said China opposed the launch, which violated U.N. Security Council resolutions that call for an end to North Korea’s nuclear and missile tests.

China is North Korea’s largest source of trade and aid, and Trump has complained that Beijing is not doing enough to pressure Pyongyang. Beijing counters that its influence is overstated and suggests that Washington’s refusal to talk directly to North Korea is impeding progress toward a solution.

“The root cause of the (North Korean) nuclear missile issue is its differences with the U.S. and South Korea,” Geng told reporters at a regular briefing.

Geng said China, a permanent member of the U.N. Security Council, has been “completely and comprehensively” implementing Security Council resolutions on the nuclear issue. He said Beijing “has been striving for a settlement of the Korean Peninsula issue by proactively engaging in mediation and promoting peace talks.”

Although generally dismissive of sanctions, Beijing has signed on to successive rounds under the U.N. Security Council, and last month banned more items from being exported to North Korea, including plutonium and dual-use technologies that could aid its nuclear program.

Geng urged all sides to refrain from provocative action and said China would continue participating in Security Council discussions in a constructive and responsible way.

Beijing appears concerned that the U.S. and South Korea will speed up the planned deployment of an advanced missile defense system in South Korea designed to counter a missile attack from the North following the latest launch. Beijing objects to the system because it would possibly be able to observe Chinese military movements.

Shi Yuanhua, a Korean studies professor at Shanghai’s Fudan University, said that from Pyongyang’s perspective, it was a good time to launch a missile because the new U.S. administration hadn’t decided what approach to take with North Korea, and Beijing was at odds with Washington and Seoul over the anti-missile system.

“Whether or not to abandon nuclear weapons concerns North Korea’s core national interests and there is no way for China to get it to change its stance with a few words of persuasion, and it can’t solve the problem by applying a ban on exports,” Shi said.

“The key for solving the problem lies in the hands of the U.S. If the U.S. is willing to sit and talk with North Korea, China will be happy to promote it,” he added.

A Communist Party newspaper said in an editorial Monday that the timing of Sunday’s launch, a day after the end of China’s 15-day Lunar New Year period, suggests Beijing’s participation in U.N. Security Council sanctions is having a “positive effect.” Last year, North Korea launched a long-range rocket on the eve of China’s most important holiday, in a snub to its chief ally.

(AP)