A prominent Egyptian activist says he has been released after authorities prevented him from boarding a plane and held him overnight.

Khaled ElSayed told The Associated Press that a "high degree of confusion" surrounded his detention.

Security officials could not immediately be reached for comment.

ElSayed says he was taken from the Cairo International airport and moved from one security office to another across the city where officials checked whether he was wanted for any crime.

He says he was then freed Friday without an explanation as to why he was held.

He says he still plans to travel to Qatar.

Egyptian authorities have been cracking down on dissent, jailing thousands, on the basis of legal provisions that rights groups say are designed to tighten public space.