Forces loyal to Laurent Gbagbo launched an offensive Saturday in Abidjan's Abobo district, a key support base of his rival for the presidency of Ivory Coast, Alassane Ouattara, the army said.

"We have just launched a major offensive to rid Abobo of terrorists. It's a make or break operation," a source at the defence forces' headquarters told AFP.

Heavy gunfire could be heard in Abobo and from the neighboring district of Cocody, which is home to Gbagbo and where public television is also situated, according to residents.

One resident told AFP he had seen four tanks, four troops carriers filled with soldiers, and two pick-ups with mortars on the streets of the neighbourhood.

Ouattara was the internationally recognised winner of a November run-off presidential election but Gbagbo has refused to leave office and still controls many of the main levers of power, including the armed forces.