Thousands took to the streets of the Sudanese capital Khartoum on Thursday to protest military rule, AFP correspondents reported.
"Down with Burhan's rule," protesters chanted in reference to army chief General Abdel Fattah al-Burhan, who seized power in a coup last year. "Even if we die, the military will not rule us."
In central Khartoum, security forces fired tear gas and water cannon to block protesters from marching towards the presidential palace, one witness said.
Some carried banners calling for justice for those killed in previous protests while others chanted, "Burhan, Burhan, back to the barracks and hand over your companies," a reference to the Sudanese military's economic holdings.
It was the first time on Thursday in months of protests against an October coup that internet and phone services had been cut, and security forces were more heavily deployed than in recent weeks.
Staff at Sudan's two private sector telecoms companies, speaking on condition of anonymity, said authorities had ordered them to shut down the internet once again on Thursday.
Phone calls within Sudan were also cut and security forces closed bridges over the Nile between Khartoum and its twin cities of Omdurman and Bahri - another step typically taken on big protest days to limit the movement of marchers.
Earlier, protesters barricaded some of the capital's main thoroughfares with stones and burning tires, witnesses said.
On Wednesday, medics aligned with the protest movement said security forces shot dead a child during protests in Bahri, bringing the number of protesters killed since the coup to 103.
There was no immediate comment from authorities, who have previously said that peaceful protests were allowed and casualties would be investigated.
The protests mark the third anniversary of huge demonstrations during the 2019 uprising that overthrew long-time autocratic ruler Omar al-Bashir and led to a power-sharing arrangement between civilian groups and the military.
Burhan said on Wednesday the armed forces were looking forward to the day when an elected government could take over, but this could only be done through consensus or elections, not protests.
Mediation efforts led by the United Nations and the African Union have so far yielded little progress.