Pope Francis wraps up the Uganda leg of his three-nation Africa tour Sunday after vast crowds held euphoric celebrations in his honour, heading to his most dangerous destination: the conflict-ridden Central African Republic.

Huge crowds of Ugandans greeted Francis as he honoured Christians martyred for the faith on the second leg of his first trip to Africa, which he dubbed "the continent of hope".

The 78-year-old pontiff received a rapturous welcome as he visited a martyrs' shrine at Namugongo, just outside the capital Kampala, to honour more than 40 Christians who were executed in the 19th century for refusing to recant their faith.

Francis, who railed against corruption and wealthy minorities who hoard resources at the expense of the poor in neighbouring Kenya, struck a more optimistic tone when he arrived in Uganda on Friday.

"The world looks to Africa as the continent of hope," he said in his opening speech, hailing the east African nation for accommodating hundreds of thousands of refugees from neighbouring war-torn states.

In CAR, one of the poorest and most unstable countries in Africa, rights groups hope the Argentinian pope will address the religious violence that has torn the country apart for more than two years.

Thousands of believers are expected to pour into the capital Bangui to see him, many of from neighbouring countries, and workers have been in overdrive paving potholes in the streets and preparing the cathedral square in the pope's honour.

Stalls have sprung up across the capital selling everything from Vatican flags to paper crowns welcoming the pope in the local sango language: "Nzoni gango na tobwa Francois!".

"We are very pleased to see the pope. He knows that things have happened in our country and maybe he has come to ask God to save us," said Fidele Nodjindorom who lives in a camp for the displaced that the pope is due to visit.

'No particular surprises'

Francis is due to fly out of Uganda around 0600 GMT for Bangui.

The country was plunged into chaos after former president Francois Bozize was ousted in a coup in March 2013.

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The mainly Muslim rebels behind the coup went on a bloody rampage that triggered the creation of the equally dangerous anti-Balaka militia in mostly Christian communities.

Concerns about the pope's safety have been running high ahead of his visit and the head of the Vatican's law enforcement, Domenico Gianni, has spent several days consulting with local security forces in Bangui.

The Vatican's spokesman said Saturday Francis' itinerary had been confirmed and all is expected to go ahead as planned, "if there are no particular surprises".

He is scheduled to visit a mosque in the flashpoint PK5 district, a maze of dirt-red roads and flimsy shacks that epitomises the sectarian conflict tearing apart impoverished nation.

The PK5 area was the epicentre of an unprecedented wave of violence pitting majority Christians against minority Muslims in late 2013 and early last year.

Francis is also due to celebrate mass in the Barthelemy Boganda sports stadium and visit a camp for people who have been displaced by the violence.

"Everything has been done to ensure the safety of the pope... there is no real threat," said CAR public security minister Chrysostome Sambia, although he admitted there have been reports of "ill-intentioned groups in some areas".

At the height of the massacres, around one in five of CAR's 4.6 million people were displaced and half the population forced to live on humanitarian aid.

Ilaria Allegrozzi, from rights group Amnesty International said the pope "has a real opportunity to call for the protection of civilians of all faiths, and use his great moral authority to help reduce the tension that has recently resulted in deadly violence".