Talks on moving Sudan towards civilian rule have been suspended for three days by the country's military leaders, who demand protesters clear roadblocks.
In a televised statement, the Transitional Military Council (TMC) said barricades outside a designated zone in Khartoum should be removed.
The setback comes hours after the TMC and the opposition agreed a three-year transition period to civilian rule.
Shots were fired on Wednesday as soldiers tried to clear barricades.
Protesters in Khartoum said at least nine people were wounded, but that figure could not be verified. Similar violence on Monday left at least six people dead and protesters say those responsible must be held to account.
Sudan has been run by the military council since long-time President Omar al-Bashir was toppled last month, but it has struggled to return the country to normality.
Protesters emboldened by Mr. Bashir's downfall have continued to stage a huge sit-in outside military headquarters in the capital, demanding full civilian government.
What do the two sides say?
In his televised address, TMC leader Lt-Gen Abdel Fattah Abdelrahman Burhan said talks were being suspended "to help prepare an atmosphere for completing the deal".
He called on protesters to dismantle roadblocks, open bridges and "stop provoking security forces".
Earlier, Rashid al-Sayid, a spokesman for the opposition Alliance for Freedom and Change, told AFP news agency: "The military council has told us that the protesters must dismantle the barricades and go back to the sit-in."
Another opposition leader, Ahmed Rabie, confirmed the talks had stalled, saying the military wanted roads in Khartoum and elsewhere reopened before it returned to the negotiating table.
What has already been agreed?
At a joint news conference on Tuesday night, TMC spokesman Lt Gen Yasser al-Atta said a deal had been struck for a three-year transition period to a civilian administration.
He said a final agreement on power-sharing would be signed with the opposition alliance within 24 hours. That would include forming a sovereign council which will rule the country until elections.
Gen Atta said the opposition alliance would have two-thirds of the seats on a 300-member transitional legislative council, while the rest would be taken by other groups.
Earlier, protest movement spokesman Taha Osman said the sides had agreed on the structure of future authorities - a sovereign council, a cabinet, and a legislative body.
What is the background?
In December, demonstrators took to the streets over a government decision to triple the price of bread. The protests soon grew into widespread anger against the president's 30-year rule.
Five weeks into the protests, on 17 January, witnesses said state forces had fired live ammunition at protesters and killed a doctor.
He had been treating injured protesters in his home in Khartoum when police reportedly fired tear gas into the building.
He was one of the dozens of people killed during the anti-government unrest.
As anger mounted, protesters staged a sit-in from 6 April outside military headquarters in Khartoum to demand the army force the president out.
Five days later, the president was overthrown by the military.
A military council assumed power on 11 April, but demonstrators stayed put, insisting that it transfer authority to a civilian administration.
Initially, talks between the ruling generals and the protest organisers had shown little sign of progress.
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