Colombian President Juan Manuel Santos and FARC Commander Rodrigo Londono signed an agreement Monday to end their 52-year war at a ceremony in Cartagena, Colombia.
Before a white-clad crowd of more than 2,000 at an outdoor plaza at the city's convention centre, Santos and Londono, known by his nom de guerre Timoshenko, signed the accord ending the Cold War-era conflict - the Western Hemisphere's longest-running war.
Dressed in white shirts in a symbol of peace, the two former enemies shook hands, as the crowd burst into applause. Londono pinned a lapel pin in the shape of a dove, formerly worn by Santos, to his shirt.
In another symbolic gesture, each signed the 297-page agreement with a pen forged from a recycled bullet and inscribed with the phrase "bullets wrote our past. Education, our future."
Each hailed the agreement as a new era for Colombia and the world.
"There is one war less in the world, that of Colombia," Santos said.
He praised Londono and FARC for their decision to "exchange bullets for votes, arms for ideas," and swore to defend their right to express their beliefs in the political sphere.
Londono asked forgiveness on behalf of FARC for "all the pain we have caused," and praised Santos as a "courageous partner" for peace.
But he made clear FARC has given up violence - but not its struggle.
"No one has given up his ideas here," he said, vowing the political movement to rise from FARC's ashes will continue its fight for "true democracy and social justice."
Among the witnesses to the historic signing were 14 heads of state and a host of top diplomats as well as 400 victims of the war and more than 100 guerrillas.
The emotional crowd at times interrupted the ceremony with cheers, chanting "yes, we did it" and joining Santos in a chant of "no more war."
But there was a moment of tension as Londono's speech was interrupted by a Colombian Air Force fighter jet zooming overhead.
Visibly surprised, he recovered quickly to quip, "thank goodness it's coming this time in a salute to peace, not to drop bombs."
Representatives for both sides finalized the deal August 24 in Havana after nearly four years of negotiations.
The treaty includes provisions for political participation by the FARC and transitional justice for war crimes, as well as rural reforms and reintegration of demobilized guerrillas into civilian life.
UN Secretary-General Ban Ki-moon, who joined Santos and Londono on stage, congratulated them on the peace accord, saying "this is how healing begins."
He pledged UN support for the peace to come, while cautioning that challenges remain.
"The challenge now is to convert the vision that was so carefullycrafted in Havana into transformative change here in Colombia," he said.
"As we celebrate this extraordinary achievement, I encourage theparties to remain as strongly committed to implementing theagreements as they were to reaching them," he added.
In the next half-year, about 8,000 remaining FARC fighters will relocate to 23 designated regions of Colombia to turn over their arms in a process to be overseen by the United Nations.
The European Union announced earlier it would "suspend" FARC from its list of terrorist organizations immediately after the deal is signed, and stands ready to provide 600 million dollars in aid to support Colombia and implement the peace deal.
In order to take effect the peace accord must be approved in a national referendum to be held Sunday.
The government has been joined by supporters from across the political spectrum in urging voters to support the deal, and recent polls show more than half of likely voters will vote yes.
But the peace has its detractors, among them far-right former president Alvaro Uribe, who lashed out at the deal on Twitter Monday, urging Colombians to vote no.