CAIRO - A web page casting doubt on the religious credentials of the family of Egyptian presidential hopeful Mohamed ElBaradei has become the latest focus of an online battle for votes.

The creators of a Facebook page carrying images of ElBaradei's daughter Laila at events serving alcohol and wearing a bikini on a beach are anonymous. But the aim seems clear: to discredit her father's campaign for political change, and a possible run for president next year, in a country that is overwhelmingly Muslim.

The web has become a main field of political conflict in Egypt, where around a quarter of the 78 million population are aged 18-29. It is also one of the few public arenas where opposition and pro-government voices can spar openly.

The authorities are quick to quash public political protests, and severely restrict the activities repress the main political opposition, the Muslim Brotherhood.

But online, opposition forces can draw levels of support that could never be mustered on the street.

A Facebook page backing ElBaradei, the former head of the U.N. nuclear watchdog who has called for constitutional change, now numbers a quarter of a million followers.

The number of his online supporters shot up after state newspapers, using more traditional media weapons, disparaged ElBaradei in coverage and columns earlier this year.