Gunfire broke out and ambulance sirens wailed as hundreds of angry victims of a failed pyramid scheme protested in Sudan's war-torn Darfur region on Sunday, with reports of at least four people killed.
Residents said a dozen people died in the protests in El-Fasher, capital of North Darfur state, while an aid worker put the toll at between four and 10 and Al-Shuruq television said three civilians and six policemen were killed.
"There have been four to 10 deaths as well as 20 to 30 people injured," the humanitarian worker told AFP on condition of anonymity.
North Darfur police chief Abdelrahman Al-Tayeb Abdel Rahman said three demonstrators were killed and 25 injured.
Police used batons and tear gas to break up the protest and arrested 104 people for trying to "destroy" property in El-Fasher, he said in a statement.
Aid workers said the shooting started early in the morning, forcing them to stay indoors.
"We have heard sporadic gunfire but it is not fighting," Kemal Saiki, an official of the United Nations-African Union Mission in Darfur (UNAMID), told AFP earlier of the protest in El-Fasher.
"We have instructed our personnel to stay at their workplace," said the official of the force, which is based in El-Fasher.
Dirar Abdallah Dirar, a demonstrator contacted by telephone, said police had opened fire as the protesters tried to march on the house of the state governor, Mohammed Yussif Kibir.
"There have been casualties," he said.
Tension has been simmering for weeks in El-Fasher where thousands of small investors have lost millions of dollars in a "Ponzi scheme," a fraud involving the payment to investors of funds contributed by new investors.
According to local residents, the governor had promised during Sudan's elections last month to compensate the victims but failed to keep his word. His office was unavailable for comment on Sunday.
But local authorities said that two people have been arrested in connection with the swindle.
"This situation has been brewing for weeks. I knew it would blow up one day or another," said another humanitarian aid worker in El-Fasher, which has around half a million inhabitants.
Many investors had sold land or ploughed in their savings to take part in the get-rich-quick scheme.
The marketplace in the centre of El-Fasher has been renamed "Al-Mawasir Souk (market)," after the local colloquial Arabic for a swindle. Al-Mawasir has also become the name used across Sudan for the scam.
Governor Kibir gave assurances on Friday to local and religious leaders that the authorities were not implicated and that investors would have their funds or property returned, state news agency SUNA reported.
Kibir also accused opposition candidates who had lost in last month's elections of fuelling tensions in a bid to destabilise the fragile situation in Darfur, SUNA said. He did not identify them.
"Sunday's protests appear to be organised and I don't think it is over," a humanitarian worker who spoke on condition of anonymity said.