United States President Donald Trump said Monday he would decide soon on whether to send more weapons to Taiwan, after Chinese President Xi Jinping warned him not to do so.

“I’m talking to him about it. We had a good conversation, and we’ll make a determination pretty soon,” Trump said, adding that he has a “good relationship” with the Chinese leader, whose country claims the self-ruled island of Taiwan as its territory.

In a phone call with Trump on 4 February, Xi called for “mutual respect” in relations with the United States, while warning Washington about arms sales to the democratically run island.

“The Taiwan question is the most important issue in China-US relations... The US must handle arms sales to Taiwan with caution,” Xi said, according to China’s state broadcaster.

Trump and Xi are due to meet in Beijing in April.

China’s Communist Party has never ruled Taiwan, but Beijing claims the island of 23 million people is part of its territory and has not ruled out the use of force to annex it.

Washington does not officially recognize Taiwan, but is the island territory’s main military backer — although the tone of that support has softened slightly under Trump.

The United States approved $11-billion worth of arms to Taiwan in December, Taipei said.

Shortly thereafter, China launched major live-fire drills to simulate a blockade around Taiwan’s key ports.

While Trump has adopted a softer tone on support for Taiwan in his second term, the issue remains a thorn in US-China relations.