Anti-Mubarak protests are increasing in frequency

It was the largest such rally in a series of anti-government protests which began in December.

Thousands of riot police stood by as the protesters chanted "No to Mubarak", but they did not intervene.

Campaigners are opposed to Mr Mubarak seeking a fifth six-year term and are urging freer presidential elections.

Earlier this month, about 100 people held a protest in Cairo calling for an end to Mr Mubarak's political dominance and for constitutional change.

Election call

In the latest rally - the fourth since December - about 500 protesters gathered in a public square outside Cairo University.

There is no use of betting on the regime's promises of reform Egyptian Movement for Change

The demonstrators sported yellow stickers bearing the word "Enough" in Arabic and chanted anti-government slogans, such as "No to Mubarak", and "Leave, have mercy on us".

Thousands of riot police with batons and shields surrounded the demonstrators but did not attempt to disperse the crowd.

The protesters from the Egyptian Movement for Change called for multi-candidate presidential elections.

"There is a widespread feeling that there is no use of betting on the regime's promises of reform, in light of the monopoly of authority and wealth, and ignoring the chronic problems which are gripping the country," the group said in a statement.

Mr Mubarak, 76, has been in power since the assassination of former President Anwar Sadat 1981, and there is widespread speculation in Egypt that he is grooming his son, Gamal, 41, to succeed him.