At least 22 people were killed in a string of raids on villages in Central African Republic this week, a local official and state radio said on Friday, as an escalation of violence threatened to derail a visit by the pope and crucial elections.

Pope Francis has already hinted that his trip, scheduled for 28 and 29 November, could be cancelled if the attacks worsen, though government and church authorities in the capital Bangui have sought to offer assurances that the visit will be peaceful.

The former French colony descended into inter-religious violence two and a half years ago after mainly Muslim Seleka rebels seized power, sparking reprisal killings by Christian anti-Balaka militias.

Armed men cut the throats of 10 people in the village of Ndassima on Monday before carrying out an overnight attack nearby in Mala, said local administrator Yves Mbetigaza.

"They came from two places, some from Bambari and others from Mbres," he said.

While a report on national radio described the attackers only as armed members of the Peul ethnic group, Mbetigaza said they were Seleka fighters, adding that eight villagers were kidnapped in Mala and dozens of others were missing.

Six hunters were killed on Thursday in the village of Bandambou, Mbetigaza said.

The killings put the death toll from violence this week at over 30. And though dozens have died in inter-religious fighting in Bangui since late September, the village raids highlight the rampant insecurity that plagues much of the countryside.

The government this week announced 27 December as the date for a first round of presidential and parliamentary elections meant to restore democratic rule more than two years after Seleka toppled President Francois Bozize and his government.

Central African Republic is currently governed by a transitional authority.

However, nearly 40 political parties, including Bozize's supporters, as well as factions of the rival Seleka and anti-Balaka armed groups said on Friday it would be impossible to hold polls before the end of the year.

They claimed they would not recognise the interim government after 31 December  and called for a leader to be chosen to head a new transitional authority to govern for a maximum of 18 months.

French soldiers and U.N. peacekeepers have struggled to contain the recent flare-up of violence. The U.N. mission, known as MINUSCA, plans to add some 750 troops and 140 police before the elections.

Some of the U.N. troops should be in place in time for the pope's visit and France has paused a drawdown of its Sangaris mission until after the elections.

A French defense ministry official said Paris had nonetheless warned the Catholic Church of the potential security issues.

"We've informed the Vatican authorities that Pope Francis' visit carries risks for himself and for hundreds of thousands of believers who could be there to see him in a pre-election period," the official said.

However Vatican sources said on Friday the trip would go ahead despite warnings from France.