Two people have been killed in the Khartoum area in riots sparked by the lifting of government fuel subsidies, police and the family of one of the victims said Wednesday.
The deaths since Tuesday take to three the number of people who have died since demonstrations erupted in central Sudan on Monday before spreading to the capital.
Protests that began late Tuesday in Khartoum lasted until dawn on Wednesday, an AFP correspondent said.
On Monday, the government announced steep price rises for petroleum products after suspending subsidies in a bid to reform the economy.
Witnesses told AFP that on Tuesday, protesters ransacked and then torched offices of the ruling National Congress Party in Khartoum's twin city of Omdurman.
"The people want the fall of the regime!" chanted hundreds of demonstrators, echoing the Arab Spring mantra first heard in Tunisia in late 2010.
One student was killed in the Omdurman protests, named to AFP by his family as Omar Mohammed Ahmed al-Khidr.
Police said that another man was killed in Khartoum, without naming him, and that other civilians and police were injured.
"Most areas in Khartoum saw unrest and unauthorised gatherings aimed at damaging property and allowing looting, necessitating police intervention," a statement said.
It said one man was killed in the capital "while trying to steal the property of a citizen who fought back".
The protests first erupted in Wad Madani in Al-Jazeera state southeast of Khartoum on Monday, where one man died.
They later spread to the streets of Khartoum, Omdurman and Nyala, capital of South Darfur state.
Oil prices at the pump have shot up to 20.80 Sudanese pounds ($4.71) a gallon from 12.50 pounds ($2.83), while diesel has risen from 8.50 pounds a gallon to 13.90 pounds.
Inflation in Sudan is already running at 40 percent.
President Omar al-Bashir said on Sunday the subsidies had reached "a level that is dangerous for the economy".
Sudan lost billions of dollars in oil receipts when South Sudan gained independence two years ago, taking with it about 75 percent of the formerly united country's crude production.
Since then Sudan has been plagued by inflation, a weakened currency and a severe shortage of dollars to pay for imports.