Two years after a popular uprising in Sudan led to the end of a 30-year old dictatorship, protests are expected on Wednesday in the capital Khartoum.
The transitional government has introduced tough economic reforms, and has won support from international lending institutions.
On Tuesday, the International Monetary Fund (IMF) approved a $2.5bn (£1.8bn) loan for Sudan.
But high inflation and the end of fuel subsidies have left many Sudanese struggling.
There are also concerns that forces loyal to the old regime are seeking to undermine the transition to democracy.