TAIPEI • Taiwan President Tsai Ing-wen appointed the ruling pro-independence party's former chairman as premier yesterday, a day after incumbent William Lai said he was resigning, along with the entire Cabinet, in response to local election defeats.

The election losses last November presented a major challenge to Ms Tsai, who came under mounting criticism at home over her reform agenda while facing renewed threats from China, which considers Taiwan its own.

Ms Tsai appointed Mr Su Tseng-chang, a two-term former chairman of her Democratic Progressive Party (DPP), as premier. She said Taiwan faced challenges amid rising Chinese threats and trade tension between key backer the United States and China.

"Taiwan's democracy and development must face certain challenges," said Ms Tsai, adding that China was looking to force its "one country, two systems" structure on the island.

Mr Su, 71, vowed to lead the administration amid the challenges and learn from earlier mistakes. "The situation is difficult and the task is tough," he said.

The resignations add to the multiple challenges facing Ms Tsai. Amid the ongoing trade war between the United States and China, Taiwan's two largest trading partners, Chinese President Xi Jinping has ratcheted up the pressure, calling in a speech last week for the beginning of talks on an eventual unification of the two sides of the Taiwan Strait. Ms Tsai rejects China's claims to sovereignty over Taiwan.

"No matter who Tsai appoints as the next premier, it will be difficult for her administration to improve their performance," said Professor Jou Jyh-bang from National Taiwan University's Graduate Institute of National Development.

"In the year ahead, there are external pressures as the US-China trade war is likely to have a negative impact on Taiwan's economy, and it's also unlikely she'll be able to achieve a breakthrough in cross-strait relations. She faces a very tough path to win re-election."

Ms Tsai's appointment of a new premier will be key to her chances of staying in power beyond next January's presidential vote. The new administration will be tasked with winning back public support after the DPP suffered a heavy defeat to the China-friendly opposition Kuomintang in local elections in November last year.

Mr Lai is the second premier to quit since Ms Tsai took office in 2016. It is standard practice in Taiwan for leaders to quit when their party loses a major election, and Mr Lai had initially offered to resign in the immediate aftermath of last November's vote before Ms Tsai persuaded him to stay on.

Taiwan's premier forms the Cabinet and runs the government on a day-to-day basis.

Mr Su was appointed premier in 2006 by former president Chen Shui-bian, who infuriated Beijing and strained Taiwan's relationship with the US during his tenure from 2000 to 2008.

Popular among the DPP's core supporters, he has led Taiwan's most populous New Taipei City for years. He was defeated by a candidate from Kuomintang in November last year.

Some from within Ms Tsai's party have urged her not to seek re-election. She has not explicitly said whether she would run for president next year.

REUTERS, BLOOMBERG