An Egyptian court on Saturday sentenced 51 people to two years in prison for taking part in protests last month, officials said.
Nearly 300 people have been arrested and charged for taking part in the demonstrations against Egypt's decision to transfer control of two strategic Red Sea islands to Saudi Arabia as part of a border demarcation agreement negotiated in near total secrecy.
The 51 were convicted of breaking a 2013 law that effectively bans protests.
The officials said 18 of the 51 were sentenced in absentia. Thirteen minors were referred to juvenile court over the protests, they added. The officials spoke on condition of anonymity because they were not authorized to speak to the media.
April's protests were the largest since President Abdel-Fattah el-Sissi was elected in 2014. As military chief, el-Sissi had led the overthrow President Mohammed Morsi a year earlier amid massive demonstrations demanding the Islamist leader step down.
Also on Saturday, prominent activist Sanaa Abdel-Fattah gave herself up to police to start a six-month sentence passed against her last week for insulting the judiciary.
Abdel-Fattah, who comes from a family of well-known activists, was brought in for questioning last month over accusations that she was inciting protests. She refused to answer the prosecutors' questions on the grounds that the judiciary was controlled by the executive branch of government and she did not want to be part of what she described as a charade. She has refused to appeal the conviction.
The widely publicized comments led to her being charged with insulting the judiciary.
Her surrender and subsequent transfer to prison Saturday was reported by her family and friends in social media posts and confirmed by the officials.
El-Sissi and members of his government routinely praise the judiciary as independent and objective, but activists counter that the justice system, including judges and prosecutors, are beholden to the government. They also report widespread abuses by the police, including the torture of suspects.
Thousands of Morsi supporters and scores of pro-democracy activists have been jailed since 2013. Hundreds more were killed in clashes with security forces during protests in the months after Morsi's ouster.
El-Sissi has said human rights in Egypt must not be judged by Western standards, arguing that his government is seeking to safeguard rights while fighting Islamic militants and struggling to revive the nation's ailing economy after years of unrest.