The Colombian government and the ELN rebels signed a cease-fire agreement in Cuba on Friday.

Preparations for the cease-fire, which will come into full force on Aug. 3 and last 180 days, are due to begin immediately, the two sides said at a joint news conference.

The cease-fire announcement is good news for the embattled Petro, who is facing allegations at home of financial irregularities in his election campaign, threatening other aspects of his planned political and social reforms.

The leftist Petro, who attended Friday´s cease-fire announcement, early in his tenure promised an ambitious plan for total peace in the South American nation long plagued by domestic conflict.

The Havana negotiations stalled in mid-May after Colombian President Gustavo Petro questioned the group´s unity of leadership, prompting a rebuke from the ELN, which at the time said talks had entered into "crisis."

"This effort to look for peace is a light of hope that conflicts can be solved politically and diplomatically," top rebel negotiator Pablo Beltrán said at the ceremony.

The talks were originally scheduled to conclude with an official ceremony on Thursday but were postponed as the parties asked for additional time to work on final details. Petro traveled to the island for the ceremony, saying it could herald an "era of peace" in Colombia.

Negotiations between the sides after being terminated in 2019 when the rebels set off a car bomb at a police academy in Bogota killing 21 people.

Following that incident, the government of then President Iván Duque (2018-2022) issued arrest warrants for ELN leaders in Cuba for the peace negotiations. But Cuba refused to extradite them, arguing that doing so would compromise its status as a neutral nation in the conflict and break with diplomatic protocols.

Talks relaunched in November shortly after as Colombia’s first leftist president.

Petro has pushed for what he calls a "total peace" that would demobilize all of the country’s remaining rebel groups as well as its drug trafficking gangs. He has questioned whether senior ELN leaders have full control of a younger generation of commanders who he has suggested are focused more on the illegal drug trade than on political goals.

The ELN was founded in the 1960s by union leaders, students and priests inspired by the Cuban revolution. It is Colombia’s largest remaining rebel group and has been notoriously difficult for previous Colombian governments to negotiate with.

In 2016, Colombia’s government signed a peace deal with the larger FARC group that ended five decades of conflict in which an estimated 260,000 people were killed.

But violence has continued to affect rural pockets of the country where the ELN has been fighting the Gulf Clan and FARC holdout groups for the control of drug trafficking routes and other resources.