With rebel groups joining forces, the incumbent accusing his rival of fomenting a coup and Russia sending troops to keep the peace — tensions are high ahead of this week’s election in the Central African Republic.

The poll on Sunday is set to be a crucial test for a two-year-old peace agreement that has failed to fully quell rebel violence and for Russian sway in the country as it seeks to expand its global sphere of influence.

President Faustin-Archange Touadéra, a Russian ally, is expected to win a second term on Sunday against 15 other candidates in the mineral-rich country after the constitutional court rejected the candidacy of ex-president François Bozizé because he is under UN sanctions.

If Mr Touadéra lost, or his victory was disputed, it could destroy the peace agreement most of the country’s rebel groups signed in February 2019, said Hans De Marie Heungoup, of the International Crisis Group (ICG). That deal, which was partly brokered by Russia, has frayed.

“If the elections are not conducted very well, they have the potential to spoil even the very little stability that the country has got,” he said. A deepening security crisis would have regional implications, threatening neighbouring Chad, Sudan, South Sudan and Cameroon.

Armed groups, which have proliferated since the peace deal, control roughly two-thirds of the country despite the presence of a 13,000-troop UN peacekeeping mission. In recent days, at least three armed groups have joined forces, taking control of a number of villages on the roads out of the capital Bangui, while the country’s fourth-largest city Bambari was briefly seized by rebels on Tuesday. The government has accused Mr Bozizé of planning a coup using the armed groups, which he has denied.

Russia has sent hundreds of troops at Mr Touadéra’s request, according to the CAR government, while the UN peacekeeping force is on its highest alert. The G5+ group — which includes France, Russia, the US, EU, African Union and World Bank — issued a joint statement on Sunday calling on the rebel groups and Mr Bozizé to lay down their arms.

Mr Bozizé, a former general who appointed Mr Touadéra as prime minister in 2008, returned to CAR last year after six years in exile. He is the subject of an international warrant for alleged assassinations and torture, which he denies.

“The biggest security problem at the moment is not the armed groups but what François Bozizé will do after the election,” said Thierry Vircoulon, research associate at the Paris-based Institut Français des Relations Internationales.

If Mr Touadéra won in the first round of what was likely to be an election fraught with irregularities, “then the whole of the opposition will understand that they have lost everything . . . and they will realise that they don’t have much to lose in starting a new rebellion”, Mr Vircoulon added.

Moscow has cultivated Mr Touadéra as an ally through arms deals and the powerful Kremlin-connected Wagner Group, whose mercenaries train local soldiers and protect the president and whose national security adviser is a former Russian spy.

“You can’t be a global power if you are only in the Middle East or Balkans, you need to be everywhere, and being in CAR is a good door for the [central Africa] sub region”, including bigger, more resource-rich economies such as Congo-Brazzaville or Cameroon, said ICG’s Mr Heungoup.

“Russia had a monopoly in Sudan, which is now being challenged by the US so CAR could be taking more importance,” he said.

While Russia is the most influential foreign country in politics and Mr Touadéra has turned away from France, the former colonial ruler remains a key donor and French companies, including oil company Total and telecoms provider Orange, do business in CAR.

Earlier this month, Facebook disrupted a disinformation campaign linked to the French military that targeted francophone Africa, touted French policy in the region and criticised Russian involvement in CAR.

Both countries have supported rebel groups, according to an October report by the Washington-based watchdog group The Sentry.

A Touadéra defeat would constitute a significant loss for Moscow, while France had less at stake because its influence in the region was both wider and deeper, said Mr Heungoup. Still, CAR has long been seen by France as among its closest francophone African allies.

“Having one of their very, very close countries moving out of their sphere of influence, symbolically and geopolitically, will be a big blow, said Mr Heungoup. “And [doubly] so because this gap will be filled by Russia.”

Like much of sub-Saharan Africa, CAR — one of the poorest countries in the world — has escaped the worst of the health impacts of the pandemic. But its economy has been battered, and 1.9m of its 5m people are now food insecure, up by 300,000 from last year and expected to rise by another 400,000 by mid-2021, according to the UN.