Donald Trump said on Wednesday he would speak to Taiwan’s President Lai Ching-te, an unprecedented move for a US leader that could roil US relations with China.

“I’ll speak to him,” the US president told reporters at Joint Base Andrews in Maryland before boarding Air Force One when asked about Lai. “I speak to everybody … We’ll work on that, the Taiwan problem.”

Responding to Trump’s comments on Thursday morning, Taiwan’s foreign ministry said Lai would be happy to speak to the US leader, according to Reuters.

US and Taiwanese presidents have not spoken directly since Washington shifted diplomatic recognition to Beijing from Taipei in 1979. However, as president-elect in late 2016, Trump broke decades of diplomatic precedent when he spoke to then-Taiwan President Tsai Ing-wen.

The political fallout from that call saw China’s government lodge a complaint with the US government, while Trump’s transition team played down the significance of the conversation.

Beijing has never renounced the use of force to take control of the democratically governed island. It has been angered by longstanding US military support for Taiwan to deter Chinese military action.

Trump’s comments was the second time in a week he said he intends to speak to Lai, dispelling initial speculation that his first mention of it after meeting China’s leader Xi Jinping last week was a verbal slip.

A call between the leaders had not yet been scheduled, according to a person familiar with the matter.

The White House did not immediately respond to a request for comment on when such a call might happen or what would be discussed. China’s embassy in Washington also did not respond immediately.

Trump administration officials have noted that Trump has approved the sale of more weapons to Taiwan than any other US president, but he has also described future weapons sales as a “very good negotiating chip.”

Trump has repeatedly touted his relationship with Xi as “amazing”. After last week’s trip to Beijing, Trump said he has not decided whether to proceed with a major weapons sale worth up to $14bn to Taiwan, adding to uncertainty about US support for the island.

In an attempt to pressure Trump, Beijing is now reportedly withholding approval for a potential summer visit to China by the Pentagon’s undersecretary of defence for policy, Elbridge Colby.

Beijing has signalled to Washington that it cannot approve Colby’s trip until Trump decides on how he will proceed with the weapons sale, according to the Financial Times, citing people familiar with the matter.

Any direct US-Taiwan conversation would ordinarily anger China, which sees the island as its own territory.

However, Trump’s language has sent mixed signals to Taipei. While Lai has welcomed the chance to speak to Trump, the US president’s reference to the “Taiwan problem” echoes Beijing’s phrasing. Lai, who Beijing views as a separatist, said earlier on Wednesday that if he got the opportunity to speak to Trump, he would say his government is committed to maintaining the status quo across the Taiwan Strait, and that it was China that was undermining peace with its massive military buildup in the Indo-Pacific.

“No country has the right to annex Taiwan. The people of Taiwan pursue a democratic and free way of life, and democracy and freedom should not be regarded as provocation,” Lai said.

Under US law, Washington is required to provide Taiwan with the means to defend itself, and both Republican and Democratic US lawmakers have urged the Trump administration to continue with weapons sales.

Underscoring Taiwan’s strategic importance to the US, the island of 23 million people is the fourth-largest US trading partner, behind China, which has 1.4 billion people. Much of that trade is based on exports to the US of advanced semiconductors, which fuel the global economy.

With Reuters