BANGKOK (AP) — China’s foreign minister said his country and the United States should overcome obstacles between the nations ahead of an expected summit next month between U.S. President Donald Trump and Chinese President Xi Jinping.

Wang Yi met with U.S. ambassador to China David Perdue on Wednesday and called on both sides to “focus on the positive agenda, properly manage differences, remove interference and overcome obstacles to high-level exchanges between the two countries,” Chinese state broadcaster CCTV reported Thursday.

China-U.S. relations “still face various risks and challenges,” he acknowledged in a statement released by CCTV.

Trump and Xi met in May in Beijing and pledged to keep the relationship stable and maintain the fragile trade truce. Trump invited Xi to meet Sept. 24 in the U.S. but the exact date of the Chinese leader’s visit has not been confirmed.

Since then, however, the U.S. and China have continued to take targeted economic action against each other including the U.S. banning Chinese-made robots and China banning American entities engaging in trade and other activities in China.