BBC News, Khartoum
Tens of thousands of Sudanese are peacefully calling for President Omar al-Bashir to step down.
But when online channels start cutting their services, they become more difficult to spread messages on behalf of their leader, protesters say.
Since 2007 internet and mobile phone coverage have been throttled in Sudan, making things more difficult for demonstrators.
And since the government blocked YouTube in February to stop activists posting videos of the protests, the organisations that support them have run into even more problems.
“They are going to cut it in the morning and can turn it off at any time,” said one activist at the Sakr al-Diwani mosque in Khartoum’s suburbs.
“But we have to use these means,” the cleric said.
The mosque is well known as the hub of the civil disobedience campaign against the government, from which the protesters have dwindled.
The regime’s growing concern about the protests is evident from the opposition to internet and mobile phone cuts and last week, the arrest of journalist Taha El Ghandour for publishing pro-democracy calls on Facebook.
“Twitter was once a powerful tool and the government is now trying to shut it off,” said one senior government official familiar with Sudanese digital life, who did not want to be named.
“That’s why it used to be fine but then we started cutting the internet, the BlackBerry has been shut down, and now they’ve blocked the internet again,” he added.
Activists are talking about using SMS messaging, but said mobile companies were shutting down messaging services to block messages from militants.