Mali was in turmoil Wednesday as soldiers stormed the state TV and radio station in Bamako and attacked the presidential palace.
There also were reports of a mutiny at a base in the strategic town of Gao in the north, CBS reported.
A Defense Ministry official told the BBC a coup d'etat was under way, but the president reportedly denied those claims Wednesday.
There is no coup in Mali. There's just a mutiny, President Amadou Toumani Toure tweeted, according to the Financial Times.
Heavy weapons fire rang out in the capital Bamako, Reuters reported, and the mutineers, angry at the government's handling of a Tuareg rebellion in the Sahara desert north, forced the state broadcaster off air after seizing parts of the capital.
We now know it is a coup d'etat that they are attempting, a Defense Ministry official said, asking not to be named. A diplomat confirmed the clashes at the presidential palace to Reuters.
The military is angry about the government's failure to come to grips with a northern rebellion by Tuareg separatists that has claimed the lives of numerous soldiers since January.
Toure needs to leave power, that is all. The movement will only stop with the taking of the palace, said a sergeant who asked not to be named.
Toure, in power since 2002, has said he is planning to step down after April elections. The former paratroop commander overthrew a dictatorship in a 1991 coup and relinquished power a year later before returning to office via the ballot box.
The events began Wednesday morning at a military camp in the capital, during a visit by Defense Minister Gen. Sadio Gassama. In his speech to the troops, the minister failed to address the grievances of the rank-and-file soldiers, who are angry over what they say is the government's mismanagement of the fight, and the lack of arms and food supplies.
Recruits started firing into the air, according to a soldier contacted by telephone who asked that his name not be published because he wasn't authorized to speak to the press. He said they then stoned the general's car, forcing him to leave the camp in haste.
By afternoon, soldiers had surrounded the state television station in central Bamako, and by evening, troops had started rioting at a garrison in the northern town of Gao.
A freelance journalist from Sweden who was driving to her hotel near the TV station, said that trucks full of soldiers arrived in quick succession and surrounded the building.
We saw a couple of trucks, with military on them. They came and started setting up checkpoints. There were military in the streets, stopping people. People were afraid, said Katarina Hoije. When we reached our hotel which is just in front of the TV station, there were lots of military outside, and more cars kept arriving, pickup trucks with soldiers on them.
She said that they set up two machine guns facing the building. Soon after, TV stations throughout the capital went black. There was no signal on state radio.
The soldiers who took part in the attack said they want to pressure the government to listen to their demands, and not to overthrow the landlocked nation's democratically-elected leaders.