STORY: Vast crowds gathered at an airport in Democratic Republic of Congo on Wednesday (February 1) for an open-air Mass with the Pope.

Local authorities estimated the numbers at more than a million people.

This is the first full day of Francis's visit to Congo, where roughly half the 90 million population are Roman Catholics.

It is also a country riven by armed conflicts that have driven millions of people into poverty.

Addressing the faithful, Francis urged a "great amnesty of the heart."

"We need to believe that we Christians are called to cooperate with everyone, to break the cycle of violence, to dismantle the machinations of hatred. Yes, Christians, sent by Christ, are called by definition to be a conscience of peace in our world."

The United Nations says armed conflict has displaced 5.7 million people in Congo and left 26 million facing severe hunger.

More than half a million have been displaced in the country's east since March last year, when rebels from the M23 group launched a renewed offensive.

At the mass, Kinshasa resident Christella Bola said her joy at the Pope's visit was "too huge."

“It is so marvellous that the Pope has come to visit and it will mean reconciliation for our country.”

Thousands of people had spent the night praying at the airport in the build up to the service.

Addressing Catholics and other Christians that may be involved in the fighting, Francis said that the Lord was telling them to "lay down your arms, embrace mercy."