Mauricio Macri has been sworn in as president of Argentina, in a ceremony boycotted by his predecessor, Cristina Fernandez de Kirchner.
Mr Macri took the oath of office in Congress and is giving his inaugural speech, where he said he would work for all Argentines.
But he will receive the sash and baton of office at the presidential palace.
Ms Fernandez insisted this should also take place in Congress and refused to attend either ceremony.
After his swearing in, Mr Macri told Congress: “As president I want to be a citizen who can communicate with all Argentines, to tell you about my doubts, my beliefs and my hopes.
“Politics for me is not a competition to see who’s got the bigger ego. It’s working together for the good of the people.”
He vowed to work “tirelessly for you in these coming four years”.
Late on Wednesday Ms Fernandez had bid farewell to supporters in an emotional speech, urging people to take to the streets if they felt betrayed by the new centre-right government.
This is the first time since the end of the military dictatorship in 1983 that a president has not attended the inauguration of a successor.
The conservative Mr Macri triumphed in last month’s election, promising to move from a largely state-controlled economy under the leftist Ms Fernandez to one that is more free market-orientated, easing trade and currency controls.
He has also promised to improve relations with the US.
In his speech in Congress he said those who had voted for him wanted three goals – zero poverty, an end to drug trafficking and the unity of all Argentines.
He said: “The country has people who think differently but it is not divided. The elections are over now, the moment has come for us to come together to move forward.”

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