Jakarta – Four people were injured on Saturday in clashes that marred a joint Muslim-Christian peace rally in Indonesia's Ambon city, the scene of three-year-old sectarian violence.

A group of unidentified people armed with machetes attacked Muslim and Christian residents parading in the city's Wai Hong district to celebrate a peace accord signed last month, the official Antara news agency said.

Police and troops fired warning shots to halt the violence, Antara said. Two people were taken to hospital with serious injuries while another two suffered slight cuts. The attack forced rally participants to disperse. At least eight motorcycles and a number of pedicabs were set on fire by the attackers.

On Wednesday Muslims and Christians mingled freely for the first time in years in Ambon. Witnesses said people from the two faiths hugged each other or shook hands. In the past three years, the city has been divided into closed Christian and Muslim districts.

Ambon is part of the Maluku "spice island" chain, where Christian and Muslim leaders on February 12 signed an agreement to end the sectarian bloodshed. The violence began in Ambon in January 1999 with a minor neighbourhood quarrel and quickly spread to other islands in the Malukus, leaving some 5,000 people dead and half a million homeless.

The two sides vowed to halt all conflict and agreed to disarm. Police have set a deadline of Friday for people including soldiers or police to surrender illegal weapons.

More than 80 percent of Indonesia's 214 million people are Muslims but in some eastern regions, including the Malukus, Christians make up about half the population.