Internet and mobile services appeared to be disrupted in Sudan's capital Khartoum on Sunday ahead of planned protests against military rule, Reuters witnesses said.
All bridges directly connecting to Khartoum were also closed, a Reuters witness said.
Sunday's protests come after six people died and hundreds were injured in nationwide demonstrations against military rule on Thursday. The death toll since the security forces' crackdown began in October is now 54, the Central Committee of Sudanese Doctors said.
The military took power in an Oct. 25 coup that ended a power-sharing deal with civilian political forces. That deal, agreed in 2019, was supposed to pave the way for a transitional government and eventually elections following the overthrow of long-time leader Omar al-Bashir.
Protests against military rule have continued even after Abdallah Hamdok was reinstated as prime minister last month, with Sunday's demonstrations marking the 12th round of major protests since the coup.
The demonstrators have demanded the military play no role in government during a transition to free elections.
Al Hadath TV quoted an adviser to military leader Abdel Fattah Al-Burhan as saying the military would not allow anyone to pull the country into chaos and that continued protests were a "physical, psychological, and mental drain on the country" and "would not achieve a political solution."
On recent occasions when communications have been disrupted, sources at telecoms companies have told Reuters that authorities demanded providers cut their services. Officials could not immediately be reached for comment on Sunday.
In a televised speech on Friday, Burhan said disputes over power and the loss of lives meant everyone "should use the voice of reason.
"The only way to rule is by popular mandate through elections," Burhan said.
Sudan's Sovereign Council, which Burhan leads, on Friday denounced the violence that accompanied Thursday's protests, adding it had ordered authorities to take all legal and military measures to avoid a recurrence and "nobody will go unpunished".
Last week, the council reinstated powers of arrest and detention to the intelligence service.