The network blackout could also freeze e-wallets that many people depend upon amid a widespread cash shortage.

Aid agencies have warned of rising hunger in Sudan and famine-like conditions in some areas, as a result of fighting between the Sudanese army and paramilitary Rapid Support Forces since April.

Two of the networks had been offline since Friday, when telecom sources and the army-aligned state news agency said the RSF had shut down the networks belonging to MTN Sudan and Sudani. Zain Sudan is now also offline, Netblocks said.

An RSF source has denied responsibility and the companies have not publicly blamed anyone for the outages.

(Reporting by Nafisa Eltahir; Editing by Kevin Liffey and Andrew Heavens)