By Matthew Tostevin
ABIDJAN, Feb 20 (Reuters) - Ivory Coast's army attacked rebels with helicopters on Thursday after accusing them of breaking a truce, while fleeing villagers told how the insurgents had killed people and hacked them with machetes.
It was the most serious flare-up since a stalled peace deal last month and comes with tension rising on both sides because of a row over whether rebels will get key security posts in a contested coalition government.
Against the backdrop of growing unease, France said security for the new government would be provided by troops from West Africa and the former colonial power.
Leaders of the Patriotic Movement of Ivory Coast (MPCI) set off for France for new talks to try to put a cabinet in place and end a war that has left thousands dead in the world's top cocoa grower.
Although the main rebel group said it knew of no clashes near the central sugar-growing town of Zuenoula, villagers who fled the surrounding countryside said their homes had been attacked by a band of rebels early on Wednesday.
"They set fire to houses and they slashed people with machetes. They slit one young man's throat and they killed another," said a man from Boi Zera village, speaking by telephone from loyalist-held Zuenoula.
HELICOPTER STRIKES
Helicopters backed ground troops as the army launched what it called a clean-up operation. It said one soldier was killed and 12 wounded in a rebel assault on Wednesday.
"If you attack us then we will strike back with the means at our disposal," army spokesman Jules Yao Yao said.
The conflict has fractured a country that was once seen as an island of stability in a region beset by strife and driven more than one million people from their homes.
Despite sporadic fierce fighting against two rebel factions in the west, the main front has been largely quiet since a ceasefire agreed four months ago.
At the weekend, the MPCI backed off from a threat to attack unless President Laurent Gbagbo applied last month's French-brokered peace accord in full -- including an unwritten agreement to give them the defence and interior ministries.
Gbagbo's supporters in the mainly Christian and animist south say the president was pushed by the French into a deal that gave too much to rebels whose powerbase lies among the tribes of the mostly Muslim north.
In another explosion of ethnic unrest, paramilitary gendarmes opened fire with live rounds and teargas to disperse northern youths rioting at Anyama just outside Abidjan after a northerner was killed in a house-to-house search for rebels. One protester died of a bullet wound.
FRANCE RENEWS PUSH
Opening a two-day summit with African leaders in Paris, French President Jacques Chirac renewed his calls for Ivory Coast's leaders to stick to the peace plan.
"It is now up to all Ivorians, and in particular their representatives, to work with determination and in good faith to revive a society at peace with itself once more," Chirac said.
A close Gbagbo aide denounced Chirac's warning of the growing reach of international law for leaders who abuse their power as an apparent attempt to ratchet up the pressure on the president to toe the French line.
Gbagbo decided not to go to the summit in apparent protest at France's role in Ivory Coast. Leaders of the rebel MPCI were due to arrive in Paris on Friday for talks with consensus Prime Minister Seydou Diarra on forming the government.
Chirac's spokeswoman said the security of Diarra and the new government would be assured by troops from France and regional troops under a West African command -- certain to raise hackles among Ivory Coast's security forces.
France has committed more than 3,000 troops to protecting its citizens and trying to keep the peace in what was once the jewel of its former West African empire, but it is increasingly squeezed by the two sides.
The rebels have asked the French to get out of the way so they can advance on Abidjan. Some loyalists suspect the French of aiding the rebels.