President Juan Manuel Santos and ex-president and opposition leader Alvaro Uribe met on Wednesday Oct. 5 to discuss possible adjustments to the peace accord with the Revolutionary Armed Forces of Colombia (FARC) that voters narrowly rejected in Sunday’s plebiscite.

After more than three hours of dialogue at the presidential palace, both leaders were optimistic about the prospect of achieving peace, but neither offered specifics on how the accord might be modified.

“We put forth adjustments and initial proposals to be made to the texts in Havana to seek a new peace agreement that includes all Colombians…” Uribe said in a statement. “The President of the Republic expressed willingness to do it.”

Santos, for his part, reiterated his willingness to listen to leaders of the “No” campaign.

“We are very close to achieving a stable and lasting peace with more civil support,” Santos stated. “If we all have this willingness and contribute responsibly and calmly, we will achieve peace.”

The meeting, the first between Santos and Uribe since 2010, came amid rising tension over the future of the country, and fears that the results of the plebiscite could lead to a new flare-up in a conflict that has killed more than 220,000 people and displaced over five million during five decades.

On Tuesday, Santos placed a deadline to hash out an agreement, announcing that Colombia’s bilateral ceasefire with the FARC will end on October 31. But Colombia’s defense ministry said on Wednesday that the ceasefire could be extended “for the security of civilians, members of FARC and security forces.”

Since leaving office in 2010, Uribe has become one of the most hardline opponents of Santos and the peace process with the FARC. The ex-president mobilized millions of Colombians to vote against the peace deal in the run up to Sunday’s plebiscite.

The razor-thin margin of victory of the “No” campaign on Sunday—53,894 votes out of a total of nearly 13 million—has thrust Uribe into a pivotal role in which he could act as kingmaker for any agreement with the rebel group, a role that FARC leaders have rebuked.

“If we leave peace in Uribe’s hands, the devil will take the country,” said FARC commander Iván Márquez in his Twitter account.

The sit-down between the two leaders followed a meeting between Santos and ex-president Andrés Pastrana, who led unsuccessful peace talks with the FARC from 1999 to 2002.

Pastrana told reporters that the meeting was “productive” and requested that the Colombian government immediately open “areas of concentration,” or encampments, for the FARC, where rebel troops would be going to be stationed once a final deal is signed.

“This is important because with the verification of the United Nations and the protection of the military, the FARC guerrilleros will have the reassurance that we are going to advance in this process,” Pastrana told reporters on Wednesday at the Casa de Nariño, the presidential palace.

For its part, the international community reiterated its support for Colombia’s peace process in the wake of Sunday’s plebiscite, including U.S. Secretary of State John Kerry, who spoke with Santos by phone on Tuesday.

“ acknowledged that difficult decisions lie ahead for Colombia, and welcomed the statements by Senator Alvaro Uribe and FARC leader Rodrigo Londoño reaffirming their commitment to peace and openness to dialogue,” department spokesman John Kirby said in a statement.

Santos, who was defense minister during Uribe’s second term, oversaw some of Colombia’s most successful military operations against the FARC, including an airstrike in Ecuador that killed FARC commander Raul Reyes in 2008, and the liberation of former presidential candidate Ingrid Betancourt and 14 other hostages held by the rebel group.

Although Santos was once Uribe’s handpicked successor, the two leaders now find themselves on opposite sides of the aisle. But the prospect of a lasting peace accord may depend upon how well the two leaders work together and how much the FARC is willing to concede.