Bogota, Colombia: Colombia will turn the page on a half-century conflict that has stained its modern history with blood when the FARC rebels and the government sign a peace deal on Monday.

President Juan Manuel Santos and the leader of the Revolutionary Armed Forces of Colombia (FARC), Rodrigo Londono -- better known by his nom de guerre, Timoleon "Timochenko" Jimenez -- are set to sign the accord at 5:00 pm (2200 GMT) in a ceremony in the colorful colonial city of Cartagena on the Caribbean coast.

It will be preceded by a tribute to the Colombian military and police, presided over by Santos, and a prayer for peace and reconciliation at an 18th century Catholic church in Cartagena's old town.

The guests will include UN Secretary-General Ban Ki-moon, US Secretary of State John Kerry and a cortege of Latin American leaders -- notably 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.

The ceremony is the second-to-last step in ratifying the peace deal.

Colombians will vote on it in a referendum on October 2. Recent polls show the "Yes" camp in the lead.

- 'New chapter' -

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

Over the decades, the conflict has drawn in several leftist rebel groups, right-wing paramilitaries and drug gangs, leaving a legacy of death and destruction: more than 260,000 people killed, 45,000 missing and 6.9 million forced to flee their homes.

"We are turning the page on the war to begin writing a new chapter of peace," Santos said Wednesday in an address to the United Nations after submitting the 297-page accord to the Security Council wrapped in the yellow, blue and red of the Colombian flag.

FARC delegates unanimously ratified the deal Friday at a national conference in El Diamante, a remote and sweltering site deep in the rebels' traditional stronghold in southeastern Colombia.

"The war is over," declared their chief peace negotiator, Ivan Marquez, to a burst of applause and cheers from rebel delegates dressed in civilian clothes.

If all goes according to plan, it will be the FARC's last meeting as a guerrilla army. Under the deal, the group is now to relaunch as a political party.

- Fourth bid for peace -

The rebels came to the negotiating table after being weakened by a major army offensive led by then-defense minister Santos, who served in the post from 2006 to 2009 before becoming president.

After an army raid killed the previous FARC leader, Alfonso Cano, in 2011, Timochenko, his successor, wrote to Santos proposing fresh peace talks -- the fourth such effort, following failed attempts in 1984, 1991 and 1999.

The talks opened in Cuba in November 2012.

Working through a six-point agenda one item at a time, delegates concluded the final accord on August 24.

The deal covers justice and reparations for victims of the conflict, land reform, the FARC's relaunch as a political party, disarmament, fighting the drug trafficking that has fueled violence in the world's largest cocaine-producing country, as well as implementing and monitoring the accord.

It also grants an amnesty for "political crimes" committed during the conflict, although not for the worst atrocities, such as massacres, torture and rape.

Those responsible for such crimes will face up to 20 years in prison, with lighter sentences if they confess.

FARC fighters have vowed to now leave their mountain and jungle hideouts and hand in their weapons in a UN-supervised process.

The government has not yet opened peace talks with a smaller guerrilla group, the National Liberation Army, or ELN.