Taiwan President Tsai Ing-wen will transit through Houston and San Francisco during a January visit to allies in Latin America, her office said Friday, prompting China to repeat a call for the United States to block any such stopover.

Tsai's office declined to comment on whether she would be meeting members of U.S. President-elect Donald Trump's team, but the U.S. mission in Taiwan, the American Institute in Taiwan (AIT), said the visit would be "private and unofficial".

Trump angered China when he spoke to Tsai this month in a break with decades of precedent and cast doubt on his incoming administration's commitment to Beijing's "one China" policy.

An adviser to Trump's transition team said he thought "further high-level engagement for the foreseeable future is unlikely" when asked if any meetings were planned. The adviser did not want to be identified by name.

China is deeply suspicious of Tsai, who it thinks wants to push for the formal independence of Taiwan, a self-governing island that Beijing regards as a renegade province, ineligible for state-to-state relations.

China's Foreign Ministry repeated a previous call for the United States not to allow the transit and not send any "wrong signals to Taiwan independence forces".

"We think everyone is very clear on her real intentions," the ministry said, without explaining.

The United States, which switched diplomatic recognition from Taiwan to China in 1979, has acknowledged the Chinese position that there is only "one China" and that Taiwan is part of it.

Tsai is transiting through the United States on her way to and from visiting Honduras, Nicaragua, Guatemala and El Salvador. She will leave Taiwan on Jan. 7 and return on Jan. 15.

Tsai will arrive in Houston on Jan. 7 and leave the following day. On her return, she will arrive in San Francisco on Jan. 13, Presidential Office spokesman Alex Huang told a regular news briefing.

The AIT said the transit did not contradict the "one China" policy.

"President Tsai's transit through the United States is based on long-standing U.S. practice and is consistent with the unofficial nature of our relations with Taiwan," Alys Spensley, acting AIT spokeswoman, told Reuters.

"There is no change to the U.S. 'one China' policy," she added.

Spensley said Tsai's transits would be "private and unofficial". The U.S. State Department said AIT chairman Ambassador James Moriarty would greet Tsai in Houston and San Francisco.

China has claimed sovereignty over Taiwan since 1949, when Mao Zedong's Communist forces won the Chinese civil war and Chiang Kai-shek's Nationalists fled to the island.

Speaking to members of China's largely ceremonial advisory body to parliament on Friday, Chinese President Xi Jinping said next year China would make "unremitting efforts" at unification and developing peaceful relations across the Taiwan Strait, state news agency Xinhua said.

Taiwan had as many as 30 diplomatic allies in the mid-1990s, but now has formal relations with 21, mostly smaller and poorer nations in Latin America and the Pacific and also including the Vatican.