UNITED NATIONS helicopters have fired at the presidential palace, believed to be housing disputed president Laurent Gbagbo, as part of renewed assaults on his forces.

The attacks come as France authorises its military forces to take out Gbagbo’s heavy weapons, an unprecedented escalation in the international community’s efforts at forcing the strongman from office.

The office of French president Nicolas Sarkozy said UN secretary-general Ban Ki-moon had requested France’s military participation in its efforts to oust Gbagbo, who lost presidential elections in November but refused to cede power even as his nation teetered on the brink of all-out civil war.

Helicopter assaults on Gbagbo’s troops began at at about 5pm local time, attempting to prevent them from using heavy weapons at the Akouedo camp in Abidjan.

UN spokesman Nick Birnback told reporters in New York that Gbagbo’s forces have consistently used heavy weapons against civilians and peacekeepers in recent days. He says the action was taken according to the mandate the mission has from the UN Security Council.

The attacks on Gbagbo mark a dramatic escalation in the offensive to remove the political heavyweight who has refused to cede power for more than four months since he was declared the loser of the presidential election.

Frederic Daguillon, the spokesman for the French force Licorne protecting civilians in Ivory Coast said earlier Monday on France-Info radio that the total French military presence in the former French colony is 1,650.

Meanwhile, fighters backing democratically elected leader Alassane Ouattara entered Abidjan by the truckload Monday afternoon as part of a final offensive to take the last piece of the West African country still largely controlled by Gbagbo.

Residents in two different districts in northern Abidjan reported seeing soldiers advancing into the city. Thousands of troops had been amassing outside Ivory Coast’s commercial capital since last week, readying for the final battle to topple Gbagbo and install Ouattara.

International observers and governments around the world backed the results issued by Ivory Coast’s electoral commission showing Ouattara had won the November presidential election, but Gbagbo refused to give up power after a decade in office.

The two men have vied for the presidency for months, with Ouattara using his considerable international clout to financially and diplomatically suffocate Gbagbo.

After the final round of diplomatic efforts had failed, forces backing Ouattara launched a dramatic offensive last week, with forces loyal to him seizing control of the administrative capital and other towns before heading toward Abidjan.

Gbagbo’s mandate as president expired in 2005 but he had delayed elections for years in a bid to retain authority.

Additional reporting by AP