Javier Milei sworn in as Argentina's new president on Sunday, sealing the ascent of a political newcomer who gained popularity by calling for economic reforms, CNN reported.

Milei is an economist and former political commentator who, during his election campaign, spoke about his intent to slash spending, according to CNN report.

Javier Milei's predecessor, Alberto Fernandez, presided over the swearing-in ceremony before Argentina's Congress in Buenos Aires. Milei took the oath before giving his first speech as president, vowing to bring about sweeping changes.

Addressing a crowd from the grand stairwell outside Congress in Buenos Aires, Milei said, "Today, it's the start of a new era for Argentina; today we close a long and sad history of decadence and decline, and we take the road of reconstruction of our country."

He said, "Argentineans had overwhelmingly expressed their desire for change that has no turning back." Several world leaders including Ukrainian President Volodymyr Zelenskyy, and former Brazilian President Jair Bolsonaro attended the swearing-in ceremony of Javier Milei.

Israel Foreign Minister Eli Cohen attended the swearing-in ceremony of Javier Milei and called him a "clear supporter of Israel." Cohen said he and the families of abductees met Milei before the swearing-in ceremony.

Taking to X, Eli Cohen stated, "Israel's true "Havier"! Proud to represent the State of Israel at the inauguration ceremony of the president-elect of Argentina @JMilei. Millai is a clear supporter of Israel, and has spoken out in favor of moving the embassy to Jerusalem."

"Before the inauguration, I met with him together with the families of the abductees. He expressed support for the war against Hamas, said that the terrorist organization should be outlawed, and called for the immediate release of all the abductees. His election strengthens Israel's support in South America and will strengthen the alliance between the countries," he added.

Milei (53) was elected as Argentina's President in the runoff on November 19. He received 55.9 percent votes while 44 percent votes were obtained by Sergio Massa, CNN reported.

Javier Milei gained national prominence after winning the elections and promising reforms like dollarization and addressing the economic challenges faced by Argentina, CNN reported.

He has already held meetings with top US officials in Washington. Milei's economic team has collaborated with the International Monetary Fund (IMF) to develop a plan aimed at reshaping Argentina's foreign policy and bringing the country's economy out of the current crisis.

He entered the race as a political outsider on a promise to "break up with the status quo." Milei's promise to dollarize, if implemented, could bring Argentina into a new territory. Previously, no country of Argentina's size had turned over the reins of its monetary policy to decision-makers of Washington.

Milei opposes abortion rights and has called climate change a "lie of socialism." He has vowed to reduce government spending by closing Argentina's ministries of education, culture and diversity and by eliminating public subsidies, according to CNN report.

His political program also includes reducing regulations on gun control and transferring authority over the penitentiary system from people to the military, both measures are part of a tough-on-crime approach.