Heavy gunfire was heard at a protest outside the defence ministry in Sudan's capital Khartoum on Tuesday, live broadcast by Arab TV stations showed, and activists said that security forces were trying to break up the protest by force.

Activists said in a statement posted on social media that army soldiers guarding the ministry were trying to protect the demonstrators.

Both Al-Hadath TV and Al Jazeera broadcast live footage in which heavy gunfire was heard and people were running for cover. They said it was an attempt by security forces to disperse the demonstrators.

Sudan has been rocked by months of small but persistent protests that were sparked by bread price rises and cash shortages.

The demonstrations later turned against President Omar al-Bashir, a former paratrooper who had been in office since 1989.

The protests escalated on Saturday, when activists, trying to push the country's armed forces to side with them, marched towards a compound in the centre of the capital housing the defence ministry as well as Bashir's residence and the country's security headquarters and camped out there.

Security forces have made several attempts to break up the protest, but army soldiers have repeatedly come out to protect the demonstrators, often firing shots in the air and deploying soldiers on streets around the protesters.