Vodafone has described the Egyptian authorities' use of its network to send pro-government texts as unacceptable.
Egypt's government instructed Vodafone to send pro-government messages to the people of Egypt under the emergency powers provisions in its Telecoms Act, said the telecoms company.
The authorities used the same act to force a near internet blackout after protests broke out across the country towards the end of January.
"These messages are not scripted by any of the mobile network operators and we do not have the ability to respond to the authorities on their content," said Vodafone.
"Vodafone Group has protested to the authorities that the current situation regarding these messages is unacceptable. We have made clear that all messages should be transparent and clearly attributable to the originator," the company said in a statement.
France Télécom, which runs mobile carrier Mobinil, also said the Egyptian government made it send messages across its network. But these messages concerned only national security and general safety, the company told news agency Bloomberg.
Foreign secretary William Hague said in a statement yesterday: "The abuse of internet and mobile networks and, in particular, today's increased intimidation and harassment of journalists, are unacceptable and disturbing."
According to the Organisation for Economic Co-operation and Development (OECD), Egypt's internet and mobile phone clampdown may have cost the country's economy £58m.