Egyptian authorities on Wednesday released 18 people, mostly women, who were arrested a day earlier in Cairo during a solidarity rally for women in war-torn Gaza and Sudan, a lawyer said.

"All those arrested during yesterday's protest in front of the UN (Women) headquarters have been released," rights lawyer Tarek el-Awadi posted on X.

Prominent activist Lobna Darwish of the Egyptian Initiative for Personal Rights (EIPR) was among those detained at Tuesday's protest, along with rights lawyers Ragia Omran and Mahienour el-Massry, lawyer Khaled Ali had said earlier.

The rights lawyer and former presidential hopeful said "the people arrested yesterday are journalists, lawyers and students", adding that people "who happened to pass by in proximity to the gathering" had also been arrested.

Hossam Bahgat, a leading Egyptian rights defender and founder of the EIPR, said Darwish had been "arrested during a demonstration of women in solidarity with Palestine and Sudan".

The Civil Democratic Movement, a coalition of 12 opposition political parties, condemned the arrests, saying those detained had been holding "a peaceful rally... to demand an end to the war in Gaza".

"The demonstration was violently dispersed, and the activists were taken to an unknown location," the alliance said on Facebook, citing witnesses.

The movement and the Egyptian Commission for Rights and Freedoms demanded the "immediate release" of those detained.

Public protests have generally been banned in Egypt since the military seized power in 2013.

Egypt ranked 136th out of 142 countries in the World Justice Project's rule of law index, is accused by the United States of vast human rights violations ranging from prisons to freedom of expression to LGBTQ rights.

In April 2022, a presidential pardon committee was formed that released nearly 1,000 prisoners of conscience over a year, but rights organizations say three times as many people were arrested over the same period.