Guards loyal to ousted President Amadou Toumani Toure tried to stage a countercoup in Mali with the help of foreign forces, according to Mali's military junta.
"Elements from abroad, supported by obscure forces within the country, carried out these attacks. Some of them have been arrested," a junta officer said in the television message, according to Reuters.
"They are trying to take control of the airport but we will fend them off," said junta spokesman Bakary Mariko.
"The idea is to try to take control of the airport so they can fly in Ecowas troops," he said, referring to soldiers from the West African regional bloc that tried to mediate after junta leaders staged a coup late in March.
Clashes near the state broadcaster building, the airport and a major military base in Kati, just outside the capital Bamako, were continuing.
In March, an uprising by Tuaregs in the desert north toppled Toure, forcing him to flee to Senegal.
Political instability has gripped the country in the interim. The junta said it was forced to act because the government was unable to stop the Tuaregs.
However, since taking charge it has been unable to halt the rebellion, which has been joined by other Islamist groups including Nigerian terrorist sect Boko Haram.
Coup leader Captain Amadou Sanogo met the country's parliamentary speaker, Dioncounda Traoré, to discuss a transition back to constitutional rule.
Traoré is set to be sworn in as interim president to oversee the transition and to organise elections
Human rights violations
At an Ecowas summit in Abidjan, Ivory Coast, West African governments urged the soldiers to step back and let politicians rule the country.
Sanogo rejected the plan, which included sending troops to Mali to protect the president's and prime minister's office.
Charities are warning of human rights abuses in the country. New York-based Human Rights Watch said armed groups and soldiers in the north have committed war crimes.
It said it had documented crimes by separatist Tuareg rebels, armed Islamist groups, Arab militias and Malian government forces, especially in the first two weeks of April. Tuareg rebels raped young girls, Islamist militants carried out public floggings, and government forces arbitrarily detained ethnic Tuaregs, it said.
"The commanders of these groups need to stop the abuses, ensure discipline over their fighters, and punish those in their ranks responsible for these crimes," said Corinne Dufka, senior Africa researcher at Human Rights Watch.