The power-sharing government in Ivory Coast is looking increasingly shaky after former rebels and
President Laurent Gbagbo's party swapped accusations over an alleged coup plot.
Rival demonstrations were held by former rebel and government supporters
The former rebels accused France of being Mr Gbagbo's "puppet" after 11 men were arrested there at the weekend and accused of plotting to assassinate the president.
Earlier, the chairman of Mr Gbagbo's party accused the prime minister of the power-sharing government set up to end the bloody conflict, of being behind the alleged plot.
The country remains divided between a rebel-held north and the south, controlled by Mr Gbagbo.
Former colonial power France has been accused by both sides of backing their rivals since the conflict began last September.
It helped broker the power-sharing deal and some 4,000 French troops are deployed in a buffer zone between the opposing sides.
Prime Minister Seydou Diarra recently said his six-month-old administration had reached a "deadlock" as Mr Gbagbo's government and the former rebels have been unable to agree on who should control the defence and security ministries.
Rival demonstrations have also been held. In the former rebel stronghold of Bouake, tens of thousands of people have called for the release of the alleged mastermind of the assassination plot, Ibrahim Coulibaly.
In the government-held commercial capital, Abidjan, hundreds of government supporters have demanded the reinstatement of the former head of the national television, Georges Aboke.
Affi N'Guessan (l) accused Seydou Diarra (r)
He was sacked by former rebel leader Guillaume Soro, the communications minister in the power-sharing administration.
Mr Diarra is viewed by many as a neutral technocrat but Mr Gbagbo's supporters have long suspected him of sympathising with the former MPCI rebels, who are mostly Muslim northerners, like him.
"We can prove the prime minister guilty of incitement and complicity in destabilisation," said Pascal Affi N'Guessan, chairman of Mr Gbagbo's FPI party and a former prime minister.
He said it was strange that the France-based plot unfolded shortly after Mr Diarra had visited Paris.
French investigators say that those arrested have admitted to plotting to assassinate Mr Gbagbo.
However, a lawyer for Ibrahim Coulibaly, a former army sergeant who led a successful coup in Ivory Coast in 1999, says he denies the charges.
Those detained are from France, Ivory Coast and Lebanon.
Up to 30 more alleged coup-plotters have been detained in the Ivory Coast commercial capital Abidjan, officials say.
On Monday, two French soldiers were killed in a clash with former rebels in Ivory Coast - the first troops to have lost their lives while monitoring the peace agreement.