(CNN) -- The United Nations plans to add 2,000 more soldiers to its peacekeeping mission in the Ivory Coast amid escalating violence between supporters of rival politicians.
Laurent Gbagbo, the incumbent leader, is defying calls to step down after an electoral commission declared he lost the election in November.
The international community -- including the United Nations -- considers challenger Alassane Ouattara the winner of the presidential vote. Ouattara is holed up in a hotel in the main city of Abidjan under the protection of U.N. peacekeepers
Reinforcements will also include three more armed helicopters to help protect civilians, according to a spokesman.
"These helicopters will be used to promote peace and provide protection," said Hamadoun Toure, a spokesman for the U.N. mission in the country.
The 9,000-strong mission has been in the country for seven years, according to the United Nations.
World leaders are concerned that violence from the standoff will cause another civil war, which split the country into a rebel-held north and a government-controlled south in 2002.
Last week, at least six were killed when an all-women group protesting the disputed president's refusal to cede power was fired upon.
Gbagbo soldiers attacked the group, which was peacefully marching in Abidjan on Thursday, said P.J. Crowley, the U.S. State Department spokesman.
Video footage shows women screaming as thunderous gunshots are heard in the background. After the attack, bloodied bodies, flip-flops and tote bags were left scattered on the streets.
The disputed president denied his forces were behind the killings, calling it a "gross manipulation" of events
About 365 people have been killed since the standoff started in December, the U.N. said.
Hundreds of thousands have fled their homes, with about 200,000 leaving the Abidjan area alone since the clashes started.
The United Nations refugee agency has warned that its access to people in need of urgent humanitarian aid is becoming impossible amid escalating violence.