U.S. President Donald Trump on Friday said he fully understands the importance of U.S. adherence to the one-China policy, and his administration will honor it.

The remarks were made during a phone call with Chinese President Xi Jinping, following Trump’s recent letter to Xi.

Xi said he appreciated Trump’s stance, pointing out that adhering to the one-China principle is the political cornerstone of China-US relations.

The two leaders also agreed to cooperate in trade, investment, and international affairs.