VILLAVICENCIO, Colombia — Pope Francis, visiting an epicenter of violence during Colombia's guerrilla war, on Friday urged the country to rise from the "swamp" of bitterness, his message boosted by a top rebel leader's forgiveness plea.

Francis flew to the city of Villavicencio in Meta province, a vast cattle ranching area which was a hotbed of paramilitary and rebel violence during the 50-year civil war between a succession of governments and the FARC guerrilla group. As he arrived, former FARC rebel leader Rodrigo Londono, now the head of a new political party, issued an open letter to the pope asking for forgiveness for the pain and suffering the group inflicted over five decades of war.

"Your repeated expressions about God's infinite mercy move me to plead your forgiveness for any tears or pain that we have caused the people of Colombia," Londono, who goes by the alias Timochenko, said in the letter. Tens of thousands of ecstatic people in this humid area of savanna and shanty towns packed the roads as the pope, riding in the front seat of a simple car, passed by.

He was presented with a traditional Colombian straw hat when he arrived at the park to say Mass, laughing and joking as he placed the hat on his head. Francis celebrated a Mass for hundreds of thousands of people on a muddy field to beatify Pedro Maria Ramirez, a priest who was killed in 1948 during a period of political violence known as "La Violencia," and Bishop Jesus Emilio Jaramillo, killed in 1989 by the National Liberation Army (ELN) for suspected collaboration with the military.

Beatification is the last step before sainthood in the Roman Catholic Church. Both were earlier declared martyrs killed in hatred against the faith, meaning no miracles were required for them to reach this stage in the sainthood process.

In the homily of the Mass, Francis, who has made reconciliation the keynote theme of his trip, again urged Colombians not to let the hopes for lasting peace whither. Francis said the two new "blesseds" of the Church should be seen as "an expression of a people who wish to rise up out of the swamp of violence and bitterness."

Colombians have suffered from war between right-wing paramilitaries, Marxist rebels, and government forces since 1964. More than 220,000 people have been killed and millions more displaced as the war spilled into towns and rural communities.

Frances said: "Reconciliation is not an abstract word," but it called for opening the door to personal dialogue and overcoming "the understandable temptation to vengeance." Colombians are deeply polarized as they prepare to receive 7,000 former fighters of FARC into society.

Many are furious that under last year's peace deal, FARC leaders accused of kidnapping, displacements and murder will avoid jail sentences and instead may receive seats in congress as members of a new civilian political party.

"Every effort at peace without a sincere commitment to reconciliation is always destined to fail," the Pope said in a homily that was repeatedly interrupted by applause. Francis, who has received a tumultuous welcome in the overwhelming Catholic country, told leaders on Thursday that just laws were needed to erase the type of social inequality that perpetuates poverty and breeds violence.

On Friday afternoon, the Latin American pope was to preside at the centerpiece of the trip, a prayer meeting in Villavicencio with 6,000 survivors of a brutal conflict that has left millions scarred by kidnappings, massacres, rape, land mines and displacement.

He will also bless the Cross of Reconciliation, a plain white memorial to the victims, hear personal testimonies of those who have suffered and see a destroyed statue of Christ brought from the western province of Choco for his visit. The effigy was recovered from a church attacked by the FARC in 2002 in the rainforest village of Bojaya.

About 80 people were killed as they sought refuge from rebel bombings inside the humble church. The plaster figure, without arms or legs, has become an enduring symbol of the war. Francis visits Medellin on Saturday and Cartagena on Sunday before returning to Rome. — Reuters