Government warplanes and helicopter gunships pounded rebel-held towns in northern Ivory Coast for a second day on Friday, fuelling fears of a slide into all-out war in the world's top cocoa grower.
After hitting the rebel stronghold Bouake on Thursday, Ivory Coast's armed forces bombed at least three towns east and west of the insurgents' main base and sent troops towards a buffer zone policed by UN soldiers.
Henry Aussavy, a spokesman for 4,000 French troops in Ivory Coast, said three army helicopters had fired rockets in the Bonguera area east of Bouake, while two warplanes had bombed the towns of Baoulifla and Seguela to the west.
The raids were the first major hostilities since a truce signed in May last year ended fighting which had killed thousands and uprooted more than a million people. A cease-fire line cuts across the middle of the former French colony.
Ivorian army officers said an invasion would follow to chase out the rebels who have controlled the north since their failed attempt to oust President Laurent Gbagbo in September 2002.
The planes took off from the capital Yamoussoukro, 100 km (60 miles) south of Bouake, where trucks with soldiers and piles of ammunition cases were on the move overnight.
In Tiebissou, the town between Ivory Coast's capital and the rebel stronghold, Moroccan UN troops blocked the road, their guns trained south towards government forces.
The town was calm but shops were closed and Ivorian soldiers were ferried to and from in pick-up trucks mounted with heavy machineguns.
While peacekeepers were blocking the main road towards Bouake, they said they could not police all the back tracks and soldiers may be able to head north by skirting round them.
"It's true there are unusual movements by the FANCI (army) in the town, but they haven't gone past our checkpoints," said a UN officer, who declined to be named.
"There are hundreds of back roads in the zone. It is difficult for us to control them all."
Besides French soldiers, more than 6,000 UN troops are policing the so-called confidence zone around the cease-fire line.
In the main city Abidjan, militant Gbagbo supporters attacked the offices of former Prime Minister Alassane Ouattara's opposition RDR party overnight.