Special flights to Dakar have ferried 167 foreigners, including French and Lebanese nationals, out of the Ivory Coast's violence-hit city of Abidjan, the French military says.

"Seventy-seven, mostly French, left overnight and 90 in the afternoon. These were not evacuations but options given to leave," French military spokesman Frederic Daguillon said on Sunday.

"Commercial flights have not restarted, these are special flights," he said.

Earlier, UN chief Ban Ki-moon demanded Mr Ouattara take action over a massacre of several hundred people blamed on his followers, a UN spokesman said.

Mr Ouattara denied to Mr Ban in a telephone conversation late on Saturday that his forces were involved in mass killings in the western town of Duekoue, according to spokesman Martin Nesirky. Mr Ouattara said he had ordered an investigation.

"The secretary-general expressed particular concern and alarm about reports that pro-Ouattara forces may have killed many civilians in the town of Duekoue in the west of the country," Mr Nesirky said.

"The secretary-general said those responsible should be held accountable.

"President Ouattara, while denying his forces were involved, said he had launched an investigation and would welcome an international inquiry into the matter."

The International Committee of the Red Cross has put the death toll at 800 and the Caritas charity says about 1000 are dead or missing.

Foreigners flee Ivory Coast as violence rages