By ANDREW GUMBEL in Los Angeles

The armed rebellion in Haiti extended its reach over the central third of the country yesterday after 50 men led by a former Army death squad commander stormed the town of Hinches, near the border with the Dominican Republic, killing the police chief and breaking open the local prison.

The raid on Hinches, which witnesses described as a furious gun battle lasting about two hours on Monday evening, marked a sharp escalation of the 11-day-old conflict which has already claimed more than 50 lives. From their base in the port of Gonaives, the rebels - backed by some of the most sinister elements in the disbanded Haitian military - have now cut the country completely in two.

From his palace in the capital, Port-au-Prince, President Jean-Bertrand Aristide appealed for international help, while western Government leaders and aid agencies held a round of emergency meetings to consider their distinctly unpalatable range of options.

The United States has ruled out military intervention; France's Foreign Minister, Dominique de Villepin, said yesterday that a peacekeeping force would be "very difficult" to deploy while the fighting was still raging.

With any semblance of political control in Haiti rapidly deteriorating into what might best be described as a series of local gang wars, it would be very hard for the outside world to take sides even if it wanted to. President Aristide is the democratically elected leader, with two more years of his mandate to run, but his dependence on armed thugs and criminals to shore up his authority has already earned him the mistrust of most, if not all, of the international community.

The rebels, meanwhile, are being manipulated and apparently taken over by disgruntled former Army officers who, if left to their own devices, would probably return Haiti to the dictatorship and military terror of the Duvalier era. Although such a prospect is being publicly deplored, diplomatic sources in Port-au-Prince say western Governments are increasingly wondering if Haiti wouldn't be more stable - at least from their point of view - under a dictatorship rather than Aristide's deeply flawed version of democracy.

The operation in Hinches was led by Louis Jodel Chamblain, who ran death squads in the 1980s and later headed a notorious paramilitary organisation called Fraph, which terrorised Haiti in the aftermath of the 1991 coup that ousted Aristide during his first term as president.

Eyewitnesses said Chamblain's men killed the police chief, Jonas Maxime, his bodyguard and another uniformed officer.

The rebels now control the whole of Artibonite, the central region which is one of Haiti's few fertile areas of food production. They have vowed to march north of the port of Cap-Haitien, the country's second-largest city, where pro-Aristide gangs have waged a bitter campaign of repression against opposition sympathisers in recent days.

Aristide called a news conference late on Monday to deplore the violence in Hinches and said he had asked the Organisation of American States for "technical assistance".

The UN High Commissioner for Refugees has started making contingency plans for a mass exodus of Haitians, while the US Government is reported to be making plans to house tens of thousands of Haitians at its naval base in Guantanamo Bay in Cuba.