At least 14,000 people have fled the violence and political chaos in Ivory Coast, some walking for up to four days with little food to reach neighbouring Liberia, the UN refugee agency said. At least one child drowned while trying to cross a river.
The UN has said at least 173 people have died in violence over the disputed presidential run-off election held nearly a month ago. The toll is believed to be much higher, though, as the UN mission has been blocked from investigating other reports including an allegation of a mass grave.
"Food supplies are running short despite efforts by the government and humanitarian agencies to bring in more assistance," the UN refugee agency said in a statement. "Our staff report that host community houses are full and congested. In the area of Butuo, for example, there are homes where seven to 20 family members share a single room, while others sleep in corridors or on verandas."
West African leaders have threatened a military intervention if the man who the UN says lost the election in Ivory Coast does not step down. James Gbeho, president of the regional bloc Ecowas, said the group was making an "ultimate gesture" to Laurent Gbagbo to urge him to make a peaceful exit.
Mr Gbagbo has shown few signs that he plans to go, and his security forces have been accused of being behind hundreds of arrests, and dozens of cases of disappearance and torture in recent weeks. A Gbagbo adviser has said he does not believe their supporters are behind the attacks.
Mr Gbeho said the bloc would send in a high-level delegation to meet with Mr Gbagbo, but did not give details on when the delegation would go to Ivory Coast. Ecowas also did not state a deadline for Mr Gbagbo to hand over power to Alassane Ouattara, whose victory has been acknowledged by the UN, the US, the African Union and the European Union.
The threat of military intervention may add enough pressure to bring about a swifter resolution, said African security analyst Peter Pham. However, he questioned whether a force could be brought together quickly enough to have an impact.
"Nigeria - the only real military power in the AU - is unlikely to have the stomach for a drawn-out military escapade on the eve of their own presidential election," said Mr Pham, who is the senior vice president of the National Committee on American Foreign Policy in New York. Nigerian elections are expected in April.
Diplomatic pressure and sanctions have left Mr Gbagbo increasingly isolated, though he has been able to maintain his rule for nearly a month since the disputed vote because of the loyalty of security forces and the country's military. Even that, though, may disappear if he runs out of money to pay them.
Mr Gbagbo's access to the state funds used to pay soldiers and civil servants has been cut off and only Mr Ouattara's representatives now have access to the state coffers. Senior diplomatic sources say that Mr Gbagbo only has enough reserves to run the country for three months.