Fierce fighting spread across the city of Abidjan today as troops loyal to Ivory Coast's Laurent Gbagbo fended off attacks by forces seeking to install rival presidential claimant Alassane Ouattara.
The heaviest clashes centred around the state television station, which went off the air after it was attacked by pro-Ouattara forces overnight.
The boom of heavy weapons fire also rang out constantly from near Mr Gbagbo's residence and presidential palace, both of which have come under attack, as well as two major military bases - turning Ivory Coast's main city into a war-zone.
Two white MI-24 attack helicopters belonging to the United Nations peacekeeping mission circled above central Abidjan's palm fringed lagoon, but did not intervene.
Mr Gbagbo, who has refused to quit after a November election that UN-certified results showed he lost, has been hit by a number of high-level defections in the military and the African Union called on him to step down immediately.
Loyalists have fought back and a Paris-based Gbagbo adviser said his surrender was "out of the question". Alain Toussaint said Mr Gbgabo was prepared for dialogue with his opponents, but did not expand on what form that could take.
Forces supporting Ouattara, who has been recognised as winner of the November election by the African Union and Western powers, marched into Abidjan yesterday after a swift push south aimed at ousting Mr Gbagbo that met with little resistance.
Mr Gbagbo's defence forces have been much tougher in Abidjan. The UN peacekeeping mission confirmed its headquarters were fired on by his special forces yesterday, and returned fire in an exchange lasting about three hours.
Hundreds of foreigners have also been taken to a French military camp after they were threatened by looters and residents of Abidjan's leafy Deux Plateau suburb reported massive looting sprees in the security vacuum.
A security source working at the airport said it was taken over by French forces this afternoon, after UN peacekeepers took control of it the previous day.
The United Nations, which has condemned violence by Mr Gbagbo's side, also called on Mr Ouattara to rein in his forces, citing what it said were unconfirmed reports they had abducted and mistreated civilians.
Witnesses said clashes were also heard coming from Treichville, a neighbourhood where the Republican Guard has a base that is used to protect the city's main bridges. Residents also reported heavy fighting at the Agban gendarmerie base.
Corinne Dufka, senior West Africa researcher at Human Rights Watch, said witnesses in Treichville and Port Bouet reported "numerous" civilians killed by sniper fire by pro-Gbagbo forces.
Amnesty International said the city was "on the brink of ... total chaos".
Mr Gbagbo has been in power since 2000. His mandate ran out in 2005 but the presidential election was delayed until 2010, ostensibly because of instability in the country.
A Sorbonne-educated history professor who prides himself on being in touch with ordinary Ivorians, he rose to prominence as firebrand lecturer who challenged the autocratic rule of Ivory Coast's first post-independence president.
The four month standoff since the election has killed hundreds and rekindled the country's 2002-3 civil war. About one million have fled Abidjan alone and 122,000 gone to Liberia.
French forces have taken about 500 foreigners, including 150 of its own nationals, to a military camp in Ivory Coast after they were threatened by looters.
Reuters