While a rising toll was reported in clashes in Cote d'Ivoire's economic capital Abidjan on Thursday, the rival forces fought for the first time in the central region of Tiebissou since a peace accord signed in 2007, the military said.

The ex-rebel New Forces (FN) which controls the northern part of the West African country exchanged fire on Thursday with troops loyal to incumbent President Laurent Gbagbo, who has the control of the southern part including Abidjan.

The two sides stop hostilities and formed a coalition government under an agreement brokered by Burkina Faso in March 2007, after the 2002-2003 civil war.

Thursday's exchange of fire risks breaking the truce with the leaders of both sides fighting a political duel in Abidjan, where both Gbagbo and his rival Alassane Ouattara claim to have won the Nov. 28 presidential run-off.

Gbagbo's army in defense of the state broadcaster fired live rounds at supporters of Ouattara marching on the key state organ in an attempt to take it over. The toll was initially put at four, but soon Ouattara's camp said at least 18 people were killed in the clash.

Ouattara has been confined to the Golf Hotel in Abidjan since sworn in days ago. He has been under the protection of the UN peacekeeping mission, which considers him as the winner of the election. Not far away is the deployment of Gbagbo's troops.

Heavy gunfire was also heard near the hotel on Thursday in skirmishes between the army and FN fighters, who tried to break the blockade earlier this week.

The Rally of Houphouetists for Democracy and Peace (RHDP), the opposition coalition, which is fighting over the presidency with Gbagbo, have called on all Cote d'Ivoire nationals to come out on Thursday to march to the national television station, and to march to the prime minister's office on Friday, to ensure that members of Ouattara's government are installed in their offices.

Cote d'Ivoire's army on Wednesday warned the UN secretary general's representative in the West African country, Choi Young- jin, that it would hold him responsible for the "unforeseen consequences" of the march planned by Ouattara's camp.