United Nations helicopter gunships on Monday fired on two military camps, the presidential palace and the home of outgoing president Laurent Gbagbo in Cote d'Ivoire's main city Abidjan, news reports said.

The military camps of Akouedo and Agban were fired on to destroy heavy weapons used by Gbagbo's forces against civilians, according to the news agency Agence France-Presse. The attacks were a joint operation between UN and French forces.

The UN "has taken action to neutralize heavy weapons used against civilians and United Nations personnel in Abidjan," AFP quoted the French presidency as saying. "The secretary general of the UN requested the support of French forces in these operations... The [French] president responded positively to this request."

Meanwhile, armed men have abducted several people, including two French nationals, from the Novotel hotel in Abidjan a day after Gbagbo allies accused France of planning a "genocide" in Cote d'Ivoire, AFP reported.

It was not immediately clear why they were abducted.

"We confirm the abduction by armed men of several people, including two French nationals, from the Novotel hotel in Abdjan this afternoon," AFP quoted foreign ministry spokesman Bernard Valero as saying.

France has boosted its military presence in Cote d'Ivoire to more than 1,600 troops. They have taken control of Abidjan's airport and have been securing the evacuation of hundreds of foreigners.

Meanwhile, AFP quoted a spokesman for internationally recognized president Alassane Ouattara as saying its forces had begun an offensive against forces backing Gbagbo in Abidjan aimed at converging in the neighborhoods of Plateau and Cocody. The presidential palace is located in the Plateau district downtown, while Gbagbo's residence is in Cocody.