Hundreds of protesters have clashed with police in the Sudanese capital, as anti-government protests in the country stretched into a fourth week.
Police fired tear gas and used batons to disperse the crowds after Friday prayers in Khartoum, forcing many to seek sanctuary in a nearby mosque.
Protesters have also been chanting a refrain heard often in other regional uprisings: "The people demand the downfall of the regime."
Opposition leaders said that at least 30 people had been arrested following Friday’s protest, a claim denied by the Sudanese officials.
Sudanese activists estimate authorities have detained some 2,000 people since protests broke out in June, Amnesty International and Human Rights Watch said in a joint report this week.
"While the number of 2,000 detained is difficult to confirm, reports indicate that at least 100 people remain in detention in Khartoum alone," the report said.
President Omar al-Bashir has previously dismissed opposition calls for an Arab Spring-style uprising in the African country, threatening that "a burning hot summer" awaits his enemies.
Demonstrations against price hikes have sprung up in recent weeks.
The government cut public spending to compensate for the loss of about 70 per cent of its revenues when South Sudan seceded a year ago, taking with it much of Sudan's oil wealth.
Sudan has been battling an economic crisis - including a budget deficit, high inflation and a depreciating currency - since South Sudan took three-quarters of the country's oil production with it when it seceded a year ago.
Oil was previously Sudan's main source of revenues and foreign currency.
Last month, the government announced tough austerity measures aimed at stabilising the economy, a move which triggered a spate of small demonstrations that began on university campuses before spreading beyond the capital.
The protests have rarely gathered more than a few hundred people at any one time, but are an added challenge for a government which is already trying to quell multiple armed rebellions.
The protests began in mid-June at Khartoum University against the austerity measures, which have increased the fares on public transportation and doubled the prices of food and fuel.
Inflation hit 37 per cent in June -more than double the level of a year ago- adding to the hardship of people who have endured years of crises, multiple conflicts and US trade sanctions.