Sudanese police used teargas to disperse thousands of protesters who set government buildings on fire in the biggest city in the western region of Darfur on Thursday, witnesses said.
More than 2,000 people took to the streets in Nyala to demonstrate against the killing of a prominent businessman on Wednesday and deteriorating security in Sudan's second-largest city, the witnesses said.
They set several government buildings and cars on fire and burned tires, blocking roads and prompting police to fire teargas. "The people want to overthrow the regime," the protesters shouted before officers dispersed the crowd.
Authorities later issued a nightly curfew in the capital of South Darfur state, state news agency SUNA said, adding that Darfuri rebels were trying to exploit the situation and enter the city. The killing of the businessman by unknown gunmen was being investigated, it added.
"The problem of South Darfur is related to its security, and this won't go away overnight," state governor Adam Mahmoud Jar al-Nabi told SUNA, blaming tribal violence.
Law and order have broken down in most parts of Darfur since mainly African tribes took up arms in 2003 against Sudan's Arab-led government, which they accuse of discriminating against them. Khartoum denies this.
Violence is down from its peak in 2004-2005, but has sharply picked up again this year, involving the army, rebels, rival tribes and robbers.
In July, fighting broke out in Nyala when two sets of security forces clashed after a person was killed at a checkpoint. Shops and offices of international aid groups were looted during the violence, which lasted several days, according to witnesses.
The fighting in Nyala has shocked diplomats because violence in recent years had been largely confined to rural areas of Darfur.
The International Criminal Court has indicted President Omar Hassan al-Bashir and other Sudanese officials for planning war crimes in Darfur. Sudan has dismissed the charges as a political campaign against the African country.