South Africa's President Jacob Zuma has said that 13 South African troops were killed in clashes with the Seleka rebels on the outskirts of Bangui, the capital.
Zuma said on Monday that 27 South African soldiers were also injured and one soldier still unaccounted for, in intense fighting in the Central African Republic that has escalated since Saturday.
"Accordingly, we are deeply saddened by the events and developments in that country over the past 72 hours which saw violence escalating and many innocent lives lost," Zuma said.
The announcement raised questions about the future role of South Africa's 200-soldier contingent it sent to Central African Republic in January to support the government troops after the rebels launched an offensive in early December.
Al Jazeera's Nazanine Moshiri, reporting from Nairobi, said that a curfew had now been implemented and that Salaka rebels were meeting at a local hotel in the capital.
Meanwhile, the government of Cameroon said on Monday that ousted President Francois Bozize had arrived in Cameroon, seeking 'temporary refuge' before he would move on to another unspecified country.
Late on Sunday, the leader of the rebels who took over the capital declared himself president and pledged to keep a power-sharing government in place in compliance with a January peace deal.
A spokesperson for the Seleka rebels announced Michel Djotodia's claim a day after the rebels toppled the President Francois Bozize.
"The current prime minister remains in place and the cabinet will be slightly reshuffled," said Eric Massi, the spokesperson.
"Bangui is under our control and calm but we have things to do on the ground in terms of security. Looting must be stopped."
The peace deal in January created a power-sharing government composed of rebels, civilian opposition and Bozize loyalists.
The rebels, who have accused Bozize of breaking the peace agreement, raided Bangui on Thursday.
Looting and gunfire had earlier been reported across many parts of Bangui after rebels seized the presidential palace there on Saturday.
Witnesses said on Sunday that gunfire could be heard across many parts of the capital and that businesses were being looted.
"The situation is rather precarious, most residents are in their homes [because] everything has pretty much been looted," said Amy Martin, the Bangui bureau chief for the United Nations Office of Humanitarian Affairs.
She added that the looting was done by "a combination of armed elements" as well as neighbourhood residents targeting houses in the diplomatic community.
The office of UN Secretary-General Ban Ki-moon issued a statement on Monday, saying "he is deeply concerned by reports of serious violations of human rights", underscoring that those "responsible for committing such violations will be held accountable".
He condemned the seizure, calling for "the swift restoration of constitutional order".
"We have asked our citizens to remain at home. For the time being, there is nothing to be worried about," said the source. "There is no direct threat to our citizens at the moment."
France, which already has about 250 soldiers stationed in the Central African Republic, sent in another company of 150 troops to secure Bangui's international airport, a diplomatic source said.
On Sunday, the French presidency said they were determined to protect their citizens in the country and had decided to strengthen their military presence.