WASHINGTON - Amnesty International has warned of a fresh outbreak of violence in Côte d'Ivoire following the country's disputed presidential elections after some of the worst armed clashes so far broke out in the city of Abidjan today.

"This morning's is the most serious armed clash in Abidjan since the November 2010 presidential election and could plunge Côte d'Ivoire into an armed confrontation," said Salvatore Saguès, Amnesty International's West Africa researcher. "There is a real risk of the population being caught up between the fighting on both sides."

The organization has learned that at least five members of the security forces were killed early this morning during fighting with armed civilians in the neighborhood of Abobo, in Abidjan, a stronghold of the Rally of the Republicans (RDR), the party of presidential candidate Alassane Ouattara.

An eyewitness, who cannot be named for security reasons, told Amnesty International: "Around midnight, I heard heavy exchanges of fire. Nobody in my compound went out. This morning, I saw near the central bus station (gare routière) of Abobo, three military vehicles burnt out and I saw the corpse of a member of the security forces."

The clashes follow the killing of least four people in Abobo yesterday morning as residents clashed with security forces trying to conduct house to house searches. At least two police officers are also said to have been killed.

Yesterday's killings happened as young residents erected barricades, threw stones and fired shots as they clashed with security forces.

Two people were killed by the Brigade anti-émeute (BAE, Anti-riot Brigade) as the security forces searched houses. Two brothers were also said to have been killed on the street.

"While entitled to defend themselves if their life is at risk, security forces cannot carry out unlawful killings of people in their homes or in the street without arms," said Saguès.

An eyewitness told Amnesty International: "I saw security forces going to the house of Lamine Ouattara, a retired man. When they knocked at his door, Lamine refused to open. The men in uniform climbed the fence, took him out of the house and shot him dead in front of the house."

One man in his twenties was shot in the back as he ran out of his house. Coulibaly Kassoum went to seek help in a compound where he was killed by security forces.

"The security forces were beating a woman who was crying," an eyewitness told Amnesty International. "One of them put his leg on the woman's head and pointed his gun at her. When they saw Coulibaly Kassoum bleeding and asking for help, they shot point-blank at his throat and killed him."

Several eyewitnesses told Amnesty International that during their house searches, the security forces looted and robbed money and goods, including mobile phones.

Alassane Ouattara is the internationally recognized winner of a presidential poll in November 2010, but outgoing President Laurent Gbagbo has refused to step down, sparking an ongoing stand-off.