ABIDJAN, Ivory Coast - The United Nations said yesterday it has received hundreds of reports of people being abducted from their homes at night by armed assailants in military uniform and that there is growing evidence of "massive violations of human rights" since Ivory Coast's disputed election.

The statement from the U.N. High Commissioner for Human Rights came a day after the U.N. said it would remain in Ivory Coast despite demands from the man refusing to give up the presidency that roughly 10,000 peacekeepers get out of the West African country.

Navi Pillay, the top U.N. human rights official, said yesterday that more than 50 people have been killed over the past three days in Ivory Coast.

"The deteriorating security conditions in the country and the interference with freedom of movement of U.N. personnel have made it difficult to investigate the large number of human rights violations reported," Pillay said in a statement released from her office in Geneva.

It also said that the armed assailants behind the home abductions had been "accompanied by elements of the Defense and Security Forces or militia groups."

International pressure is mounting for Laurent Gbagbo to concede defeat to opposition leader Alassane Ouattara, whose victory has been recognized by the United Nations, the United States, former colonizer France and the African Union.

In Washington, the U.S. State Department yesterday ordered most of its personnel to leave Ivory Coast because of the deteriorating security situation and growing anti-Western sentiment.

The order exempts only the State Department's emergency personnel. U.S. officials also warned all American citizens to avoid travel to the West African nation until further notice.

The EU was giving Gbagbo until yesterday to concede defeat or face sanctions that would include an assets freeze and a visa ban on him and his wife. The U.N. Security Council was also expected to meet today to discuss Ivory Coast's political crisis.

Still, experts say there are few strong options for forcing Gbagbo out of office, and it is unlikely the African Union or others would back a military intervention.

"The trouble is both sides are clearly preparing now for conflict, and a cornered Gbagbo shows little sense of the national tragedy unfolding through his brinkmanship," said Alex Vines, head of the Africa program at Chatham House, an independent research center in London.