Colombia’s government and the leftist FARC rebels prepared to sign a historic peace accord today to end a half-century civil war that has killed hundreds of thousands.

A solemn ceremony on the Caribbean coast witnessed by international dignitaries will set the seal on a four-year process to end Latin America’s last major armed conflict.

"Today we are experiencing the happiness of a new dawn for Colombia," President Juan Manuel Santos said on Twitter.

He called it "a new stage in our history – one of a country in peace!"

He will sign the accord at 5:00 pm (2200 GMT) with his former enemy, FARC leader Timoleon Jimenez, at a ceremony in the colorful colonial city of Cartagena, the government said.

Santos opened the day’s events with a tribute to the Colombian military and police.

A prayer service for peace and reconciliation was scheduled later at an 18th-century Catholic church in Cartagena’s old town, led by the Vatican’s Secretary of State Pietro Parolin.

The guests at the signing will include UN Secretary-General Ban Ki-moon, US Secretary of State John Kerry and an array of Latin American leaders.

They include Cuban President Raul Castro, whose country hosted the nearly four-year-long peace talks that produced a final deal on August 24.

The 2,500 expected attendees have been invited to wear white for the 70-minute ceremony.

Once the peace agreement is signed, the European Union will temporarily suspend the FARC from its list of terrorist organizations, the bloc’s ambassador in Bogota, Ana Paula Zacarias, told RCN television.

The group could be definitively removed from the blacklist after a six-month review process.

Colombians will vote on the peace accord in a referendum on October 2.

The country’s second-largest rebel force, the leftist National Liberation Army (ELN), agreed to hold fire ahead of the referendum.

The government has yet to begin planned peace talks with the Cuban-inspired ELN, saying it must first stop kidnappings.

The FARC, a Marxist guerrilla group, launched its war on the Colombian government in 1964, in the aftermath of a peasant uprising that was put down by the army.

Over the decades, the conflict has drawn in several leftist rebel groups, right-wing paramilitaries and drug gangs, killing 260,000 people, leaving 45,000 missing and uprooting 6.9 million.

Such guerrilla armies were common across Latin America in the latter half of the 20th century. But now, 25 years after the Cold War, Colombia’s is the last major armed conflict in the Americas.