Egyptian police have arrested seven men accused of sexually assaulting and stripping a woman during celebrations in Cairo's Tahrir Square on Sunday marking the inauguration of the president.
Police were also investigating 27 complaints of sexual harassment against women in Tahrir, where tens of thousands celebrated Abdel Fattah el-Sisi's inauguration, Egyptian officials said.
The seven men were arrested in connection to an attack on a 19-year-old student, said the officials. They did not elaborate on her condition. The Interior Ministry said the suspects were between the ages of 15 and 49.
The arrests came after a video was posted on social media showing a woman being dragged naked through a large crowd at night towards an ambulance.
the ministry did not specify whether they were involved in the assault seen in the video.
Last week, authorities issued a decree declaring sexual harassment a crime punishable by up to five years in prison.
The arrests were made under the new law, the Reuters news agency reported.
Authorities investigating other reports of sexual assaults were examining a dozen videos from security cameras and mobile phones, the officials said.
They said the footage suggested an organised nature of harassment, with groups of young men consistently luring potential victims away from densely crowded spots before encircling and assaulting them.
They said many of the harassers used knives to threaten victims and those coming to their rescue.
"Between November 2012 and June 2013, about 250 cases of sexual assault or harassment by mobs or rapes using weapons were reported during protests in Cairo," Fathi Farid, of the I Saw Harassment group, told the AFP news agency.