JAKARTA - Joko Widodo, Indonesia's first leader without deep roots in the era of dictator Suharto, was sworn in as president Monday and immediately reached out to his political foes to seek support for his ambitious reform agenda.
The inauguration, which was attended by foreign dignitaries including US Secretary of State John Kerry and Australian Prime Minister Tony Abbott, capped a remarkable rise for a softly-spoken politician who was brought up in a riverside slum.
Widodo, known by his nickname Jokowi, worked his way up through local politics before securing the presidency in July following a close race against controversial ex-general Prabowo Subianto.
He is the country's first president from outside an ageing band of political and military figures who have ruled the world's third-biggest democracy since the end of the three-decade Suharto dictatorship in 1998.
But there are fears that a hostile parliament dominated by parties that opposed Widodo at the election, and the new leader's status as a political outsider, could make it hard for him to push through reforms aimed at reviving Southeast Asia's top economy and helping society's poorest.
At a ceremony in parliament, Widodo, wearing a black suit and traditional cap, stood for the national anthem alongside Susilo Bambang Yudhoyono, who is stepping down after a decade in power, before taking the oath.
During his first speech as president, he called for unity following the most bitterly fought election in Indonesian history.
"Unity and working hand in hand are prerequisites for us to be a great nation," Widodo, a 53-year-old former furniture exporter who won legions of fans during his time as Jakarta governor, told parliament. "We will never become a great nation if we are stuck with division."
"This is a historic moment for us all to move together, to work and work," the president urged, and insisted that the government would help citizens right across the world's biggest archipelago nation.
The new leader also referred to Prabowo as "my best friend" during the speech, and the ex-general responded by standing up and giving a salute.
It was the latest sign of a thaw between the pair, after Prabowo only grudgingly conceded defeat and his supporters threatened to block the new leader's reforms in parliament. However, analysts cautioned the reconciliation may be short-lived.
Tens of thousands lined the streets across Jakarta to celebrate the inauguration of Widodo, who was later expected to travel through the capital by horse-drawn carriage with new vice president, Jusuf Kalla, to the presidential palace.
In the evening the new leader, a heavy metal fan, is expected to join rock bands on stage at an outdoor concert.
About 24,000 police and military personnel were deployed to secure the day's events.
But the euphoria of the inauguration is likely to be short-lived, analysts warn, as Widodo faces up to the task of leading the world's fourth most populous country, with 250 million people spread over more than 17,000 islands, at a critical moment.
Economic growth is at five-year lows, corruption remains rampant, and fears are mounting that support for the Islamic State group could spawn a new generation of radicals in the world's most populous Muslim-majority country.
Kerry's attendance was in part aimed at seeking support from Indonesia and other Southeast Asian nations in the fight against the extremists, who have taken over vast swathes of Iraq and Syria.
Widodo's first test will be to reduce the huge fuel subsidies that eat up about a fifth of the budget, a move economists say is urgently needed but which risks sparking large street protests.
Prospects for his ambitious reforms dimmed in recent weeks after Prabowo's supporters in parliament used their majority to abolish the direct election of local leaders, a move opposed by Widodo, and win key posts in the legislature.
Prabowo's appearance at the inauguration and an unexpected meeting with Widodo Friday during which he pledged support have raised hopes that tensions are easing, but observers say the ex-general may still oppose the new leader's policies.
Widodo is also expected to announce his new cabinet later in the week.