President Laurent Gbagbo of Ivory Coast has said he will remain in power until elections are held, defying opposition demands to step down.
At least one person was injured during Abidjan's rally
Mr Gbagbo was speaking in a televised address on the night when his five-year mandate was supposed to end.
But scheduled elections have been postponed and the UN decided to keep Mr Gbagbo in power for up to another year.
Riot police earlier fired warning shots and used tear gas to disperse hundreds of opposition protesters in Abidjan.
At least one person was injured as hundreds of protesters tried to march to Mr Gbagbo's residence in the country's main city.
Ivory Coast has been in turmoil since rebels seized the north in 2002.
More than 10,000 French and UN troops patrol a barrier zone between the northern rebels - known as the New Forces - and the militias who support Mr Gbagbo in the south.
The New Forces have meanwhile proposed that their leader, Guillaume Soro, be named as prime minister.
The end of Mr Gbagbo's mandate and the tough rhetoric of the armed and unarmed opposition have increased fears for the future of the country, the BBC's James Copnall in Abidjan says.
Postponement no surprise
"The president of the Republic will carry on guaranteeing the continuity of the state... until elections are held," Mr Gbagbo said in his speech.
Laurent Gbagbo says rebels must disarm before any elections
"I will never allow the decapitation of the state of Ivory Coast," he said.
The president expressed hopes that the polls would take place well before the 12 months were up.
"That is the mission I shall give to the prime minister we will be appointing in a few days' time," Mr Gbagbo added.
He also described the rebels as "armed bands out of the control of the legitimate" authorities, accusing them of trying to further destabilise the situation in the country.
The division of the country has made it impossible to hold elections to find a successor to Mr Gbagbo, our correspondent says.
Electoral rolls have not been drawn up, he says, and it was no surprise when elections were postponed.
Several thousand opposition supporters attended a rally in Abidjan to demand that Mr Gbagbo leave office.
Women wearing white face paint danced round in circles while young men loudly shouted their rage at Mr Gbagbo.
Riot police fired in the air and used tear gas when some demonstrators tried to march to Mr Gbagbo's residence in the city centre and set alight wooden barricades.
Similar rallies are being held in the rebel-held north.
Supporters of Mr Gbagbo, known as the Young Patriots, have postponed a rally they were going to hold in Abidjan due to fears about clashes between the rival groups.
In March last year, more than 120 opposition supporters were killed by the Ivorian armed forces as they tried to demonstrate, according to a UN report.
The UN Security Council has demanded that a new prime minister acceptable to all be appointed, with reinforced powers.
Key mediators Presidents Olusegun Obasanjo of Nigeria and Thabo Mbeki of South Africa are expected in Ivory Coast in the next few days to help choose a prime minister who will be acceptable to all sides.