Mauricio Macri took office as Argentina's first non-Peronist president in more than a decade on Thursday, promising to end policies of leftist populism and revive the South American country's ailing economy.

Macri began his 4-year term in a ceremony snubbed by his predecessor, Cristina Fernandez, following a rancorous argument over where the handover of power should take place. The 56-year-old Macri, his wife and daughter were escorted by horse-riding guards through streets packed with cheering supporters waving the national flag and yellow balloons, the color of Macri's "Let's Change" alliance.

In his first speech as president, the former centre-right mayor of Buenos Aires vowed to make the economy grow, lift all Argentines out of poverty and tackle endemic graft. "Multiplying job opportunities is the only way to achieve prosperity where, today, there is an unacceptable level of poverty," Macri told lawmakers moments after taking his oath in the National Assembly.

His victory delivered a hammer-blow to the Peronist movement that has dominated Argentine politics for much of the past 70 years and which will be ready to pounce on him if his planned reforms to the fragile economy unleash a new crisis. Peronism is a now a fragmented force but many Argentines who in the same breath voice support and disdain for it have tended to turn to it in times of political and economic turmoil.

Reading from a script, Macri did not provide any fresh details on how he would unwind capital controls and import restrictions, tame double-digit inflation or narrow Argentina's yawning fiscal deficit. They are tasks that will be complicated by a central bank running low on U.S. dollars and a festering debt dispute with creditors that isolated Argentina from global debt markets and plunged it back into default last year.

Tens of thousands of Macri supporters swarmed toward the Pink House presidential palace, where Macri later received the presidential baton and sash from the Senate leader in Fernandez's absence. In the streets, firecrackers rang out in celebration as he delighted the crowd with his dad-style dancing on a palace balcony.

Macri's argument with Fernandez stemmed from his wish that he receive the presidential sash and ceremonial baton at the palace, while Fernandez insisted on holding the full ceremony in Congress, where her party has the most seats.

"Complicated legacy"

"Macri is the one who is going to restore democracy," said pensioner Lilia Mitre, who arrived at dawn to save her spot. "What we had under Fernandez was an awful autocracy," she added, echoing a complaint of Fernandez's critics that the former president listened only to a small inner circle. The ceremony was attended by regional presidents including Michelle Bachelet of Chile, Juan Manuel Santos of Colombia and Evo Morales of Bolivia, one of Fernandez's staunchest allies.

Macri's nominee for finance minister, Alfonso Prat-Gay, said he would not overwhelm the country with a blizzard of reforms on his first day in office, and reiterated that capital controls would be lifted when conditions were right. "They're leaving behind a complicated legacy," Prat-Gay told reporters outside Congress.

Macri promised to battle corruption and restore the judiciary's independence which opponents of the Peronist movement say waned during Fernandez's leadership. "There can be no activist judges from any political party," Macri said.

Fernandez's eight years in power divided the country of 43 million people. She was adored by the poor for expanding the social safety net and defending workers' rights, but reviled by others for heavy-handed state controls that hobbled the economy. A forceful orator who thrived on confrontation, Fernandez's absence from Macri's swearing-in was the first time since the 1983 end of a military dictatorship that a president had not attended the inauguration of an elected successor.