Image caption Mobile phones have played a big part in the Egyptian protests

Mobile phone firm Vodafone has accused the Egyptian authorities of using its network to send unattributed text messages supporting the government.

Vodafone was told to switch off services last week when protests against President Hosni Mubarak began.

But the authorities then ordered Vodafone to switch the network back on, in order to send messages under Egypt's emergency laws, the firm said.

In a statement, Vodafone described the messages as "unacceptable".

"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."

Likely cost

The Paris-based Organisation for Economic Co-operation and Development says that the government clampdown on internet services may have cost the Egyptian economy as much as $18m (£11m) a day or $90m in total.

The impact of the communications block could be even greater, as it would be "much more difficult in the future to attract foreign companies and assure them that the networks will remain reliable", said the OECD in a statement.

In another development, the credit ratings agency Fitch has downgraded the Egypt's debt grade by one notch to BB from BB+, citing the consequences of the continuing political unrest on the economy.

The country's debt grade has already been downgraded by two other ratings agencies, Moody's and Standard & Poor's.