Up to one million Ivorians have now fled fighting in the main city Abidjan alone, with others uprooted across the country, the UN Refugee Agency (UNHCR) said on Friday in a sharp upwards revision of previous estimates.
"The massive displacement in Abidjan and elsewhere is being fuelled by fears of all-out war," UNHCR spokeswoman Melissa Fleming told a news briefing in Geneva.
"Available estimates are that between 700,000 and one million could now be displaced," Fleming told reporters.
Ivory Coast has descended to the verge of civil war following a disputed election in November last year which Alassane Ouattara is recognised internationally to have won.
Incumbent Laurent Gbagbo has refused to cede power.
The violent stand-off has led to about 462 confirmed deaths.
The U.N. agency said those leaving were mainly residents from the districts of Abobo, Adjamame, Williamsville and Yopougon, some of the most populated areas of a Abidjan, a city of 4 million inhabitants.
"Families fleeing areas of conflict have told UNHCR monitors that they are afraid of being caught in the fire and killed by stray bullets," Fleming added.
A U.N. human rights officer said on Thursday forces loyal to Gbagbo shelled areas seen as pro-Ouattara, and had killed 50 people in the past week. Gbagbo's camp has denied such attacks.
MEDICAL STAFF FLEE ABIDJAN
The medical charity Doctors Without Borders (MSF) said in a statement it had treated hundreds of people with bullet wounds and there were no signs of the situation improving as health staff, along with many Ivorians, were fleeing Abidjan. Nearly all medical workers in six hospitals have fled, it said.
"Health centres no longer operate -- or provide extremely limited services -- because medical staff have left, they lack drugs and medical supplies, and because some have been looted," said Renzo Fricke, MSF emergency coordinator.
Residents said people were continuing to flee Abobo -- scene of some of the worst fighting -- on Friday morning following a night of sustained automatic and heavy weapons fire in the area.
"We could not sleep last night. We shut the windows but could hear the sounds of heavy weapons and were afraid," said Clementine Yao.
A Reuters reporter heard sporadic machinegun fire in the direction of Williamsville on Friday.
"Greater measures to protect civilians and meet fundamental humanitarian needs in Ivory Coast are urgently needed," said a coalition of 32 international charities in a Friday statement.
"Hundreds of thousands of people are in urgent need of food and non-food aid, including medicine ... current provision of funding for humanitarian aid is already insufficient," it added.
It urged that more funds be made available to cope with the unfolding humanitarian crisis, the deployment of extra peacekeepers to protect civilians and the establishment of a commission of inquiry to investigate human rights abuses.