Security officials say the Monday arrests were made around the Journalists' Union building in central Cairo, where dozens of people, mostly lawyers and journalists, had gathered to demonstrate. The officials spoke on condition of anonymity because they weren't authorized to brief reporters, AP reported.
Last Thursday, state media reported that Egyptian President Abdel-Fattah el-Sissi's government approved the maritime border agreement and sent it to parliament for ratification despite a court ruling the deal unconstitutional.
The transfer was announced alongside a Saudi aid package last year, leading critics to condemn it as a land sell-off. The April signing of the agreement set off the largest demonstrations of Sissi's two-year rule.