CAIRO (Reuters) – Egyptian authorities released senior Muslim Brotherhood member Mahmoud Ezzat late on Saturday after holding him without trial for more than three months, official sources said on Sunday.

Ezzat, the secretary-general of the Islamist movement”s Guidance Office, was detained on May 22 as part of a crackdown on the Brotherhood a few days before a referendum on a constitutional amendment introducing presidential elections with more than one candidate.

The Brotherhood, which is Egypt”s largest opposition group but which the government refuses to recognize, had called for a boycott of the referendum because of the conditions limiting independent presidential candidates.

Because of the restrictions, the Brotherhood does not have a candidate among the nine opposition politicians challenging President Hosni Mubarak, who is seeking a fifth six-year term in the elections on September 7.

But the Brotherhood, its eyes on parliamentary elections in November, has advised its members to take part in the presidential elections and to vote for the candidate of their own choice.

Ezzat, who is among the top four members of the Islamist movement, was the most senior Brotherhood member detained in a crackdown which began in March, when the movement started a series of street protests for political reform.

Another leading Muslim Brother, Essam el-Erian, remains in detention.

Ezzat paid bail of 2,000 Egyptian pounds and could still face charges, such as belonging to an illegal organization, the official sources said.