Britain's new Prime Minister Rishi Sunak waves to the crowd after delivering his first address to the nation outside 10 Downing Street in London, Britain, Oct. 25, 2022.

Rishi Sunak became Britain's new prime minister on Tuesday after meeting King Charles III in Buckingham Palace, where the monarch asked him to form a government after the resignation of Liz Truss.

Sunak, Britain's former chancellor of the exchequer, won the ruling Conservative Party's leadership race on Monday. (Xinhua/Li Ying)

LONDON, Oct. 25 (Xinhua) -- Britain's new Prime Minister Rishi Sunak on Tuesday pledged to "fix the mistakes" made by the Truss government and restore the country's economic stability, while warning there will be "difficult decisions to come."

"Right now, our country is facing a profound economic crisis," Sunak said in his first address to the nation outside 10 Downing Street. He officially became the prime minister after King Charles III met him at Buckingham Palace earlier in the day and invited him to form a government.

Sunak said Liz Truss was not wrong to want to improve growth, which was a "noble aim," but "mistakes were made."

Truss's attempt of using debt-funded tax cuts to spur economic growth plunged the British pound to a 37-year low against the U.S. dollar, while pushing up the cost of government borrowing and mortgage rates.

Sunak said he had been elected prime minister to "fix" those mistakes.

"I will place economic stability and confidence at the heart of this government's agenda," he said. "This will mean difficult decisions to come," he added.

The 42-year-old prime minister also said he will deliver on the party's manifesto, including a stronger National Health Service (NHS), better schools, safer streets, leveling up and building an economy that embraces the opportunities of Brexit.

"(It) was a very somber address," Wyn Grant, emeritus professor of politics at the University of Warwick, told Xinhua.

"That was an appropriate tone to strike because he does need to prepare the nation for what are going to be some very difficult decisions involving increases in taxes and cuts in public services," Grant said.

Sunak inherits an economy on the brink of recession, with energy shortages, a cost-of-living crisis and runaway inflation that defy any easy fix.

Britain's inflation rose by 10.1 percent in September as food costs keep rising. The squeeze on public spending has aggravated problems in key public services such as the NHS. British households have also been warned that they will face electricity blackouts this winter due to gas shortages.

"The big challenge is to ensure in these very difficult economic times that you can maintain a good level of public services and deal with the challenge that the National Health Service in particular is facing, but also other public services. And that is a very tough task for anyone," Grant said.

On Tuesday afternoon, Sunak appointed his new cabinet. Chancellor of the Exchequer Jeremy Hunt and Foreign Secretary James Cleverly retained their posts.

Suella Braverman was reappointed as home secretary, less than a week after her resignation from the Truss government. Dominic Raab, who was justice secretary and deputy prime minister in Boris Johnson's government, got both roles back. Ben Wallace was reinstated as defense secretary.

Britain's new Prime Minister Rishi Sunak delivers his first address to the nation outside 10 Downing Street in London, Britain, Oct. 25, 2022.

Rishi Sunak became Britain's new prime minister on Tuesday after meeting King Charles III in Buckingham Palace, where the monarch asked him to form a government after the resignation of Liz Truss.

Sunak, Britain's former chancellor of the exchequer, won the ruling Conservative Party's leadership race on Monday. (Xinhua/Li Ying)

Britain's new Prime Minister Rishi Sunak delivers his first address to the nation outside 10 Downing Street in London, Britain, Oct. 25, 2022.

Rishi Sunak became Britain's new prime minister on Tuesday after meeting King Charles III in Buckingham Palace, where the monarch asked him to form a government after the resignation of Liz Truss.

Sunak, Britain's former chancellor of the exchequer, won the ruling Conservative Party's leadership race on Monday. (Xinhua/Li Ying)

Britain's new Prime Minister Rishi Sunak delivers his first address to the nation outside 10 Downing Street in London, Britain, Oct. 25, 2022.

Rishi Sunak became Britain's new prime minister on Tuesday after meeting King Charles III in Buckingham Palace, where the monarch asked him to form a government after the resignation of Liz Truss.

Sunak, Britain's former chancellor of the exchequer, won the ruling Conservative Party's leadership race on Monday. (Xinhua/Li Ying)

Britain's new Prime Minister Rishi Sunak waves to the crowd after delivering his first address to the nation outside 10 Downing Street in London, Britain, Oct. 25, 2022.

Rishi Sunak became Britain's new prime minister on Tuesday after meeting King Charles III in Buckingham Palace, where the monarch asked him to form a government after the resignation of Liz Truss.

Sunak, Britain's former chancellor of the exchequer, won the ruling Conservative Party's leadership race on Monday. (Xinhua/Li Ying)

Britain's new Prime Minister Rishi Sunak waves to the crowd after delivering his first address to the nation outside 10 Downing Street in London, Britain, Oct. 25, 2022.

Rishi Sunak became Britain's new prime minister on Tuesday after meeting King Charles III in Buckingham Palace, where the monarch asked him to form a government after the resignation of Liz Truss.

Sunak, Britain's former chancellor of the exchequer, won the ruling Conservative Party's leadership race on Monday. (Xinhua/Li Ying)

Britain's new Prime Minister Rishi Sunak delivers his first address to the nation outside 10 Downing Street in London, Britain, Oct. 25, 2022.

Rishi Sunak became Britain's new prime minister on Tuesday after meeting King Charles III in Buckingham Palace, where the monarch asked him to form a government after the resignation of Liz Truss.

Sunak, Britain's former chancellor of the exchequer, won the ruling Conservative Party's leadership race on Monday. (Xinhua/Li Ying)

Britain's new Prime Minister Rishi Sunak delivers his first address to the nation outside 10 Downing Street in London, Britain, Oct. 25, 2022.

Rishi Sunak became Britain's new prime minister on Tuesday after meeting King Charles III in Buckingham Palace, where the monarch asked him to form a government after the resignation of Liz Truss.

Sunak, Britain's former chancellor of the exchequer, won the ruling Conservative Party's leadership race on Monday. (Xinhua/Li Ying)

Britain's new Prime Minister Rishi Sunak delivers his first address to the nation outside 10 Downing Street in London, Britain, Oct. 25, 2022.

Rishi Sunak became Britain's new prime minister on Tuesday after meeting King Charles III in Buckingham Palace, where the monarch asked him to form a government after the resignation of Liz Truss.

Sunak, Britain's former chancellor of the exchequer, won the ruling Conservative Party's leadership race on Monday. (Xinhua/Li Ying)

Britain's new Prime Minister Rishi Sunak delivers his first address to the nation outside 10 Downing Street in London, Britain, Oct. 25, 2022.

Rishi Sunak became Britain's new prime minister on Tuesday after meeting King Charles III in Buckingham Palace, where the monarch asked him to form a government after the resignation of Liz Truss.

Sunak, Britain's former chancellor of the exchequer, won the ruling Conservative Party's leadership race on Monday. (Xinhua/Li Ying)