Dissident soldiers seized the radio station in Ivory Coast's main city Abidjan on Monday, but officials said loyalist forces were quelling an attempted coup d'etat.
Heavy firing erupted late on Sunday in the centre of the commercial capital of the West African country, the world's biggest cocoa producer, where military rule ended in a wave of people power protests last October.
"The radio and the television station are currently in the hands of the soldiers," one unidentified soldier said on the radio. "The country has just turned a new page in its history."
He said that a spokesman would give a further statement shortly and told people their security would be guaranteed. The message was repeated several times.
But Interior Minister Emile Boga Doudou denied that dissident troops were in control of the radio and television stations, although he said there were soldiers inside both buildings holding workers hostage.
"They are not in control. They are fleeing at this moment," he said.
Firing, some of it sustained bursts of machine gun fire, could be heard through the night from central Abidjan.
There was no immediate report of casualties.
Prime Minister Affi N'guessan earlier told Reuters that loyalist troops had brought an attempted coup under control.
N'guessan did not say who might be behind the coup attempt in the former French colony, where elected President Laurent Gbagbo came to power in October after protests toppled army ruler Robert Guei who was trying to rig a presidential poll.
"I heard shooting and big explosions. They were close enough to shake the house," said one resident near the television station in the Cocody district.
PRESIDENT OUT OF TOWN
Diplomats said there had been firing near the official presidential residence, but sources in Abidjan and western Ivory Coast said Gbagbo had been at his home village of Mama over the weekend and was expected to return to his office on Monday.
Officials confirmed reports of an attack on the Agban camp of the paramilitary gendarmerie, which is seen as loyal to Gbagbo and sided with him during the protests that swept him to power.
Boga Doudou said the attackers had arrived in four-wheel-drive vehicles and taxis and that they had been repulsed.
He earlier told Radio France International that the government had been aware of a plot against it and was "militarily prepared".
Ivory Coast's first coup, on Christmas Eve 1999, brought Guei to power and ended the country's traditional reputation as a haven of stability in a turbulent region.
But the end of military rule has brought little calm.
At least 200 people have been killed since then in ethnic and political violence involving supporters of former Prime Minister Alassane Ouattara, who was barred by the courts from contesting the presidency on nationality grounds.
One soldier told Reuters that there was talk in army circles that soldiers from Ouattara's Muslim north had revolted, but there was no evidence to back this up.
Gbagbo last month accused Guei, who fled Abidjan during the protests, of recruiting mercenaries in neighbouring Liberia. Guei has been at his home village in the west for the past few weeks but no attempt has been made to arrest him.
Boka Yapi, head of Guei's infamous Red Brigade guard, is holed up somewhere with a group of heavily armed troops.
Even senior officials say there has been little improvement in the conditions of soldiers, whose mutiny snowballed into the 1999 coup and whose anger has spilled over into violence several times since then.
(Additional reporting by Vincent T'sas, Alistair Thomson).