Gunmen attacked a military police base early Tuesday in the Malian capital Bamako where gunfire and explosions were heard and the airport was closed, sources and witnesses said.

"This morning armed men attacked at least one military police base in Bamako. They have not been formally identified," a police source told AFP on condition of anonymity. 

Volleys of gunfire interspersed with explosions began at around 5:00 am and black smoke could be seen rising from an area near the airport.

"Bamako airport is temporarily closed due to events," an airport official said without saying how long the closure would last.