Photo/Illutration Taipei city mayor Ko Wen-je answers to media reporters in Tokyo on May 24. (Asahi Shimbun file photo)

TAIPEI--China has too many other issues to worry about at the moment, from protests in Hong Kong to a slowing economy, to give much thought to Taiwan, the mayor of Taipei, sometimes seen as a potential future president, said on Thursday.

China claims self-ruled and democratic Taiwan as its own territory, to be brought under Beijing's control by force if necessary. It regularly calls Taiwan the most sensitive issue in China-U.S. ties, Washington being Taiwan's main arms supplier.

But Taipei Mayor Ko Wen-je, who has advocated for better relations with China, told Reuters that while Taiwan was important to China, it was not currently the "core issue" that Beijing likes to portray.

"They say that Taiwan is a core issue, but I'm very clear that it isn't. Taiwan is not China's core issue," he said.

"In comparison to Hong Kong, to Xinjiang, Taiwan is not on the top of the priority list. For mainland China, there are their economic problems, their GDP has already fallen to below 7 percent," Ko added in an interview, where he switched between Mandarin and English.

Chinese-ruled Hong Kong has been rocked by anti-government protests for nearly six months, the biggest challenge to President Xi Jinping since he took charge in 2012. China has come under international opprobrium for locking up a million or more Muslims in the western region of Xinjiang as part of what it calls a de-radicalization program.

In any case, Ko said, the United States--Taiwan's most important international backer even in the absence of diplomatic ties--would not let Taiwan become formally independent or be taken over by China.

While the 60-year-old Ko decided not to run for the presidency for elections scheduled for Jan. 11, the position he holds is traditionally a stepping stone to the presidency. The three presidents preceding current leader President Tsai Ing-wen all served as Taipei mayor.

If Tsai wins re-election--and polling is on her side--she cannot then stand for a third term in 2024.

Ko, who this year formed a new political party, the Taiwan People's Party, said it was still too early for him to say if he would run in 2024, adding he would decide when his mayoral term runs out in three years time.

"Do what you should do now and let God decide," he said.

A surgeon turned politician, Ko is known for his colorful personal style. Last year he made a rap video for his mayoral re-election campaign called "Do the right thing", which quickly went viral.

Ko has sought his own path between Taiwan's two main parties, Tsai's pro-independence Democratic Progressive Party and the Kuomintang, which favors close ties with China.

Visiting the United States earlier this year, Ko told the conservative Heritage Foundation that Taiwan can be close to the United States but also friendly with China.

In July, Ko also went to Shanghai to meet the city's mayor, Ying Yong. While there, he reiterated previous comments that the two sides of the Taiwan Strait "are one family."

Ko said he had no plans so far to go to China next year.

Senior Chinese leaders are always on their guard in such meetings, as if you make a mistake in China "you will be disappeared from the world," he added, with a laugh.

"They were very, very nervous when they talked with me. Because I'm very unpredictable. We're very easy. We say what we think. They can't. They're very rigid."