Colombia's President-elect Ivan Duque has been sworn in to office, pledging to unite a divided nation behind his plan to toughen a peace accord with Marxist rebels and rekindle economic growth.
Right-wing Mr Duque, who replaces Nobel Prize winner Juan Manuel Santos, faces significant challenges.
The economy remains weak, a new wave of drug trafficking gangs have moved into areas once controlled by the Revolutionary Armed Forces of Colombia (FARC) guerrillas, and nearly a million Venezuelan migrants have crossed into Colombia looking for food and work.
The 42-year-old lawyer and former senator for the Democratic Centre party won a decisive victory against a leftist opponent in June's election.
He has promised to make adjustments to the domestically controversial peace accord with the FARC, cut corporate taxes and redouble security efforts in certain areas.
"I want to govern Colombia with unbreakable values and principles, overcoming left and right divisions," Mr Duque said in an address before dignitaries, after receiving the presidential sash in Bogota's Plaza Bolivar.
"I want to govern Colombia with the spirit of building, never of destroying."
Ongoing peace negotiations with National Liberation Army (ELN) rebels, the country's last remaining insurgent group, will be evaluated over the next 30 days, Mr Duque said.
He added that any process must be "credible" and based on an end to guerrilla criminal activity over a specified time frame.
He said he will also send an anti-corruption bill to congress and begin measures to reactivate the sluggish economy.
Mr Duque is a protege of hardline ex-President Alvaro Uribe, a harsh critic of the peace agreement, whose father was killed by rebels.
Mr Uribe, facing allegations of witness tampering and bribery that he has denied, is seen by many as the power behind the relatively inexperienced Mr Duque.
But Mr Duque, a father of three who worked at the Inter-American Development Bank before Mr Uribe asked him to take a Senate seat in 2014, has already shown independence in some cabinet choices and in a softening of his anti-accord rhetoric.
The 2016 peace deal brought an end to the FARC's part in more than five decades of war, which killed some 260,000 and saw thousands of rebels demobilise in return for amnesty.
Though its leadership will be tried for war crimes, Mr Duque is angry they will not serve jail time before taking up ten guaranteed congressional seats.
Colombia's youngest president of the modern era has not specified the changes he would make to the agreement, but anything more than cosmetic will be tough to get through a Congress that has broadly backed the deal.
