Sudan's protest movement called Tuesday for fresh rallies and rejected the military rulers' election plan after more than 35 people were killed in what demonstrators called a "bloody massacre" by security forces.
Protest leaders called on their supporters to take part in "total civil disobedience" to topple the ruling military council following the deadly dispersal Monday of a weeks-long sit-in outside the army headquarters in Khartoum.
The Transitional Military Council ousted veteran president Omar al-Bashir in April after months of protests against his authoritarian rule and had agreed a three-year transition period to a civilian administration.
But army ruler General Abdel Fattah al-Burhan announced in a televised statement the plan had been ditched and an election would take place under "regional and international supervision".
"The military council decides on the following: cancelling what was agreed on and stopping negotiating with the Alliance for Freedom and Change, and to call for general elections within a period not exceeding nine months," General Burhan said.
The Sudanese Professionals Association (SPA), which spearheaded protests against Bashir, rejected the call.
"It's not the putschist council, nor its militias, nor its leaders who decide the fate of the people, nor how it will transition to a civilian government," it said.
The SPA said Monday's action against the sit-in amounted to a "bloody massacre".
The Transitional Military Council said in a statement that it "regrets" the events, calling it a "clean-up operation" that went wrong.
Tensions remained high across Khartoum, with heavily armed members of the paramilitary Rapid Support Forces, thought to have been largely behind the crackdown, deployed in large numbers.
Despite the security presence and internet outages, residents of some areas of the capital still came out to mark the Eid al-Fitr festival a day early and to protest.
The SPA urged people to hold Eid prayers to mark the end of the holy month of Ramadan on Tuesday to "pray for the martyrs" and then "demonstrate peacefully".
In Omdurman, just across the Nile from Khartoum, a witness said by phone that the Rapid Support Forces were trying to disperse demonstrators who had put up barricades by "firing live rounds in the air".
"We gathered in our square as we usually do every year but the Rapid Support Forces and the police fired teargas and sound bombs at us and after the prayers the youth closed the main street by putting up barricades," a resident of the Bahri area told AFP.
Other streets around the city centre were almost deserted Tuesday, with many markets and shops closed and almost no cars on the roads on an overcast morning.
Flights into Khartoum were disrupted as airlines monitored developments on the ground.
The United States called it a "brutal" crackdown on protesters, who want the generals behind the Bashir's overthrow to hand over to civilian rule.
UN chief Antonio Guterres condemned the excessive use of force and called for an independent investigation.
The UN Security Council will meet behind closed doors on Tuesday to discuss Sudan, after Britain and Germany requested the talks, diplomats said.
The Central Committee of Sudanese Doctors, which is close to the protesters, said the death toll had risen to more than 35, including an eight-year-old child, with "hundreds" wounded.
Protest leaders said the large square outside army HQ where demonstrators had camped out day and night since April 6 had been cleared.
Footage published online showed protesters running from the sit-in site early Monday, shouting and carrying wounded people away on makeshift stretchers as the crackle of gunfire can be heard in the background.
"Outside the army headquarters "there is no one, but the pure bodies of our martyrs that it has not been possible to evacuate from the site," said the Alliance for Freedom and Change umbrella protest group.
Rallies against Bashir's authoritarian, three-decade rule led to his ouster in April, but protesters had remained outside the army headquarters calling on the generals to cede power to a transitional authority.
African and Western governments have been strongly supportive of the protesters but Arab governments, led by Saudi Arabia, have backed the military rulers.
The US assistant secretary of state for Africa, Tibor Nagy, said it was a "brutal and coordinated attack, led by the Rapid Support Forces militia, that mirrors some of the worst offences of the Bashir regime".
Moussa Faki, head of the African Union Commission, urged "an immediate and transparent investigation in order to hold all those responsible accountable".
But Arab governments called for renewed talks between protesters and the military. Ahead of the crackdown as talks faltered, Burhan had visited Egypt, the United Arab Emirates and Saudi Arabia.