Forces loyal to Ivory Coast presidential claimant Alassane Ouattara have seized Laurent Gbagbo's official residence in Abidjan.
The spokesman, Patrick Achi, said he did not know if Gbagbo was in the residence at the time it was seized.
Earlier, United Nations attack helicopters had fired rockets near Laurent Gbagbo's official residence in Abidjan, and also attacked two military bases in the city.
The UN had said earlier it began military operations in Ivory Coast targeting Gbagbo's heavy weapons capabilities after attacks on civilians.
The attacks came as the French government announced in Paris that its troops and UN soldiers had been given the go-ahead to start operations to ‘neutralise’ heavy weapons being used on civilians by Mr Gbagbo's fighters.
Helicopters from the UN mission, called UNOCI, worked in coordination with those from the French forces, said the UN spokesman in the country, Hamadoun Toure.
‘UNOCI helicopters fired on the Agban and Akuedo military camps as well as the palace and presidential residence,’ he said.
‘We are working with the French force Licorne, in line with our mandate and the UN resolution 1975.’
The resolution was adopted by the UN Security Council last month, when new sanctions were also agreed as part of a raft of measures to try to make Mr Gbagbo hand over power after losing November elections.
An AFP journalist saw four Licorne helicopters firing on the Agban military camp while other witnesses reported UN helicopters shooting on the Akouedo barracks.
Mr Outtarra's offensive began in the early afternoon when heavy weapons fire and explosions could be heard from the central Plateau area, site of the presidential palace.
‘The offensive has been launched,’ said Sidiki Konate, spokesman for Mr Ouattara's prime minister Guillaume Soro.
‘At 1pm, movements started towards four large corridors. We are securing our passage. The objective is to converge on Plateau and Cocody (north).
Cocody is home to Mr Gbagbo, who refuses to acknowledge that he lost elections on 28 November last.
Mr Gbagbo has rallied supporters to form a ‘human shield’ around his residence.
After bolstering forces with 300 men over the weekend, France announced another 150 would be deployed, charged mainly with protecting foreigners, taking the number to 1,650.
Meanwhile, reports have emerged of human rights abuses over the week including the massacre of hundreds of civilians in the western town of Duekoue.
The International Red Cross has said 800 died in Duekoue in one day in an incident ‘particularly shocking by its size and brutality’.
The Catholic mission Caritas reported 1,000 were ‘killed or disappeared’ and the UN mission gave an initial death toll of 330, saying that, while both camps were involved in the mass killings, the majority of deaths were caused by pro-Ouattara fighters.
