Local radio in Nyala, the capital of South Darfur state, broadcast an announcement that the schools were shut, a resident said.

Police were deployed throughout the city, he added, but there were no more demonstrations after Tuesday's violence, which was unprecedented since protests sparked by high inflation began in the capital Khartoum on June 16.

The city's main market, a focus of Tuesday's demonstration, also stayed closed on Wednesday, the resident said.

"Eight citizens were killed and 24 injured, including three police who are in a serious condition," the official SUNA news agency quoted police as saying.

They are the first officially confirmed deaths related to the scattered anti-regime protests which have taken place for more than six weeks around Sudan.

An activist youth movement, Sudan Change Now, accused security forces of firing live ammunition and said 12 people, many of them young people, were killed.

Police did not give the cause of death but said officers used a "low level of force" to control the situation after demonstrators burned a petrol station and police facilities in Nyala.

A witness told AFP police had fired tear gas at the demonstrators, who threw stones at government buildings and burned tyres in the street.

Like other demonstrators in Sudan, they repeated a call made by Arab Spring protesters around the region: "The people want the fall of the regime."

Bothina Mohammed Ahmed, spokeswoman for the South Darfur government, told AFP the demonstration started because students "rejected the price of transport announced by the government."

She added that "other groups" whom she did not identify attacked government property during the protest.

Demonstrations in Sudan began last month when University of Khartoum students voiced opposition to high food prices, starting the longest-running public challenge to the 23-year regime of President Omar al-Bashir.

Inflation reached 37% year-on-year in June and jumped almost 10 points in May.

After Bashir announced austerity measures, including tax hikes and an end to cheap fuel, scattered youth-driven protests spread to include a cross-section of people, often in groups of 100 or 200, around Khartoum and in other parts of Sudan.

Protests have dwindled during the Muslim holy month of Ramadan, which began on July 20.

But a strike by public transport drivers upset over high fuel prices has added to the burden of Nyala residents.