On national television, a group of about 20 soldiers were shown in fatigues crowding around a desk facing the camera.
They introduced themselves as the National Committee for the Reestablishment of Democracy and the Restoration of the State, or CNRDR.
"The CNRDR representing all the elements of the armed forces, defensive forces and security forces has decided to assume its responsibilities and end the incompetent and disavowed regime of [President] Amadou Toumani Toure," said their spokesperson reading from a statement.
"All the institutions of the republic are dissolved until further notice. ... The objective of the CNRDR does not in any way aim to confiscate power, and we solemnly swear to return power to a democratically elected president as soon as national unity and territorial integrity are established."
The sound of gunfire could be heard from the direction of the presidential palace.
A soldier at the palace who requested anonymity because he was not authorised to speak to the press said that the president's bodyguards had failed to defend the seat of government against the renegade soldiers, who burst in.
They searched the grounds but could not find Toure, the country's democratically elected leader who was due to step down at the end of his term next month.
The series of events that culminated in the coup began on Wednesday morning at a military camp in the capital, during a visit by Defence Minister General 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 a rebellion in the north by Tuareg separatists. The rebellion has claimed the lives of numerous soldiers, and those sent to fight are not given sufficient supplies, including arms or food. Their widows have not received compensation.
Trucks full of soldiers
Recruits started firing into the air on Wednesday, and they stoned the general's car as it raced away. By afternoon, soldiers had surrounded the state television station in central Bamako, yanking both the television and radio signals off the air for more than seven hours. By Wednesday evening, troops had started rioting at a military garrison located in the northern town of Gao, about 2 000 miles away.
A freelance journalist from Sweden who was driving to her hotel near the TV station at about 16:00 local time on Wednesday, said that trucks full of soldiers had surrounded the state broadcaster.
"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," 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.
In Washington, US State Department spokesperson Victoria Nuland said: "The situation is currently unclear and unfolding quickly," she said. "There are reports of military forces surrounding the presidential palace and movement of vehicles between the palace and the military barracks."
The Tuareg uprising that began in mid-January is being fuelled by arms leftover from the civil war in neighbouring Libya. Tens of thousands of people have fled the north, and refugees have spilled over into four of the countries neighbouring Mali due to the uprising.
The government has not disclosed how many soldiers have been killed, but the toll has been significant. In February, military widows led a protest. In an attempt to diffuse tension, the Malian president allowed himself to be filmed meeting the widows, who publicly grilled him on his handling of the rebellion.