Streets were empty across Sudan's capital on the first day of a general strike urged by protest leaders demanding the resignation of the ruling military council.

The Sudanese Professionals Association (SPA) called on people to stay at home in protest at the military's deadly crackdown last week, when security forces violently dispersed the group's main sit-in outside the military headquarters in Khartoum.

The SPA spearheaded months of mass protests that led to the military overthrow of President Omar al-Bashir in April, and called on people to remain in the streets until a full handover of power to civilians.

The group posted photos it said were of an empty Khartoum International Airport. It said airport workers and pilots were taking part in the civil disobedience.

Videos circulated online showed offices and businesses closed and light traffic, in both Khartoum and the Red Sea city of Port Sudan.

The protesters say more than 100 people have been killed since the crackdown began last Monday.

Heavy deployment of troops from the paramilitary Rapid Support Forces (RSF) was reported in several parts of the capital and its sister city of Omdurman.

Security forces removed barricades from the main roads and opened the sit-in area outside the military's headquarters for the first time since the dispersal. The SPA urged protesters to avoid clashes with the RSF.

Protesters have accused the RSF, which grew out of the notorious Janjaweed militias used by Mr al-Bashir in the Darfur conflict in the early 2000s, of leading the nationwide crackdown. The SPA has called for the force to be disbanded.

"The peaceful resistance by civil disobedience and the general political strike is the fastest and most effective way to topple the military council... and to hand over power to a transitional civilian authority," the SPA said.

It called on international agencies to refrain from dealing with the military council.