Pope Francis indicated today that his planned visit to the Central African Republic this month could be canceled if violence between Christians and Muslims there worsens.

Speaking to tens of thousands of people in St Peter's Square, he called for an end to the "cycle of violence" in the country he is scheduled to visit November 28-29 as part of a trip that will also take him to Kenya and Uganda.

Francis spoke of the "trip I hope to be able to make to that nation". He has previously simply said he would go.

A senior Vatican source said the phrasing was chosen because of the violence in the capital Bangui, where the pope is scheduled to visit a mosque in one of the most dangerous neighbourhoods.

"If the situation worsens, he will not be able to go and he is aware of that," the source said.

Last Thursday, four people were killed by mobs, bringing last week's death toll to 11, including three negotiators for the Muslim Seleka alliance visiting Bangui for peace talks.

Mostly Muslim Seleka rebels seized power in the majority Christian nation in a coup in 2013, prompting reprisals by Christian militias known as anti-balaka.

Muslims and Christians have since split into segregated communities across the landlocked former French colony. Tens of thousands of Muslims have fled to the far north, creating a de facto partition.

Apart from threatening the pope's visit, the violence might wreck plans to hold long-delayed elections in December.

On Thursday, interim President Catherine Samba Panza replaced the defence, public security and justice ministers as part of a cabinet reshuffle.

The violence has flared despite the presence of thousands of UN peacekeepers (MINUSCA), who Vatican sources have said would be involved in protecting the pope if he visits.