Sudan's military have been condemned for their violent attack on protesters in the capital, Khartoum, which reportedly left at least 30 dead.
UN Secretary General António Guterres called for an independent investigation saying he was "alarmed" by reports that officers had opened fire in a hospital.
The US said it was a "brutal attack" while the UK called it "outrageous".
Sudan has been governed by a military council since President Omar al-Bashir was overthrown in a coup in April.
The leaders of the pro-democracy movement, who demand that a civilian government take over the running of the country, said they were stopping all contact with the Transitional Military Council (TMC) and called a general strike.
What happened at the protest sites?
The security services moved on the main protest site early on Monday, activists said, and heavy gunfire could be heard in video footage.
In a statement read on national television, the military council expressed its "sorrow for the way events escalated", saying the operation had targeted "trouble makers and petty criminals" .
"During the execution of the campaign, large numbers of these groups took shelter in the sit-in square, which led some of the square's officers, based on their judgment, to follow and chase them, which led to losses and injuries."
The military, the statement added, was dedicated to protecting civilians.
Earlier, activists said the security forces had surrounded one hospital in Khartoum and had opened fire at another.
The Central Committee of Sudanese Doctors, which is close to the protesters, said 30 people - including an eight-year-old child - had been killed, and that the toll was likely to rise as not all casualties had been accounted for.
Hundreds of people had been injured, it added.