Abrupt halt in internet connectivity suspected to be work of government trying to prevent protesters organising through social media

All internet connections to Sudan were cut off abruptly on Wednesday afternoon, after riots erupted in northern Khartoum over the ending of fuel subsidies.

The move to cut connections appears to have been done by the government to prevent protesters using social media to organise riots. "From the connectivity data alone, we cannot tell whether the blackout is government directed." Doug Madory from internet monitoring firm Renesys told the Guardian. "However, it is either a coincidental catastrophic failure of all three independent internet providers and their connections out of Sudan, including a terrestrial link into Egypt - unlikely given its not just a single connection - or some centrally directed, government action."

He added: "Normally with a failure of this type that isn't governmentally directed, like a power failure or a cut cable, internet providers switch to their satellite backups, but we haven't seen that in this case. It is a total shutdown, as happened previously in Egypt."

Cutting off internet connectivity has been used by some governments in Middle Eastern countries attempting to regain control amid heated protests. The now-defunct Mubarak regime in Egypt and the Assad regime in Syria have both severed internet links to try to restrict protests. Cutting international links also makes it more difficult to upload videos of protests to YouTube.

Renesys said Sudan's internet connectivity dipped at 1030 and then dropped to zero just before 13:00 UTC on Wednesday. Arbor Networks, another internet monitoring company, confirmed the report, seeing the same dip-and-drop movement.

Sudan internet connectivity on Wednesday 25 September, as seen by Arbor Networks

Protests broke out after the Sudanese government removed fuel subsidies, with several petrol stations and a university building set on fire, Reuters reported. Security forces fired teargas to disperse dozens of protesters who have demonstrated and set fire to a police station in Khartoum.

The protests have gone on for three days after Sudan's Council of Ministers decided to stop the subsidies. That caused an immediate doubling in the price of fuel.

The cut in subsidies follows the split of South Sudan to form an independent state in 2011, which took more of the main oil-producing territory which had previously been part of Sudan. The International Monetary Fund has previously told Sudan to cut the subsidies, because they consumed more than 75% of the government's total tax revenues.