Hundreds of young people loyal to President Laurent Gbagbo have taken to the streets in Ivory Coast in recent days, clamouring for the withdrawal of UN and French peacekeeping troops and attacking UN bases, residences and vehicles across the government-controlled south.
The deaths on Wednesday were the first reported in violent protests this week by supporters of President Gbagbo, who are demanding that UN and French peacekeepers withdraw from the West African country, divided in two - a government-controlled south and a rebel-held north - by a 2002 civil war.
Government supporters began the protests this week to oppose a call by foreign mediators to end the mandate of the national parliament, which is dominated by Gbagbo loyalists.
UN bases and vehicles have been attacked by hundreds of protesters.
The United Nations meanwhile accused Ivory Coast radio stations of inciting people to arm themselves and attack the United Nations.
"This is unacceptable and must cease immediately," UN chief spokesman Stephane Dujarric said, calling the broadcasts
"particularly disturbing" as a wave of attacks on UN peacekeepers went into a third day.
Some members of the UN Security Council, meanwhile, said
the time had come to impose sanctions on Ivory Coast government or rebel leaders who were blocking the peace process.
The four were killed when demonstrators stormed a base used by the Bangladesh contingent of the UN peacekeepers at Guiglo in the west of the world's top cocoa producer.
Margherita Amodeo, a UN spokeswoman, said: "The Guiglo camp was stormed at about 4am this morning. They were repelled by Bangladeshi soldiers... I know there are four from among the attackers [who were killed]."
An Ivorian military commander, who also confirmed the deaths but asked not to be named, said UN peacekeepers had since evacuated from the western towns of Guiglo and Duekoue.
"The Guiglo camp was stormed at about 4am this morning. They were repelled by Bangladeshi soldiers..."
A French army spokesman said the four protesters who were killed had tried to take weapons and had climbed on to armoured vehicles. He said 12 more demonstrators had been injured.
In the commercial capital, Abidjan, pro-government youths blocked streets and took over state television studios from where they broadcast demands for UN and French peacekeeping troops to leave.
Late on Wednesday, Gbagbo and Prime Minister Charles Konan Banny called for their compatriots to end the street violence which has brought chaos to Abidjan and go back to work.
Following emergency talks with Nigerian President Olusegun
Obasanjo, who flew into Ivory Coast, the Ivorian leaders called on the people "to withdraw from the streets and to go back home".