Nearly 200 people, most aged between 15 and 22, were arrested during the street protests and some were subjected to "inhuman and degrading treatment, and even forms of torture," says the complaint filed by Foro Penal Venezolano at the Hague-based court on Wednesday.
The alleged abuses occurred April 15-16 in the cities of Valencia, Barinas and Barquisimeto and included forcing detainees to sing pro-government songs, dousing them with urine and beating them "multiple times with frozen water bottles," according to the complaint.
It says some female detainees were "forced to strip naked in front of other prisoners and male soldiers."
The Defense Ministry and the Attorney General's office didn't return calls seeking comment Friday.
Tensions are high in Venezuela, with President Nicolas Maduro and opposition leader Henrique Capriles trading bitter accusations after Maduro's narrow election win on April 14. Capriles claims Maduro won through fraud and thousands of his supporters protested in the streets in several cities after the election.
The government says at least nine of its supporters were killed in attacks by opposition supporters and dozens were injured. It also claims opposition supporters damaged government offices and Cuban-run neighborhood medical clinics.
The opposition vehemently denies the accusations.
Foro Penal Venezolano is comprised of more than 200 lawyers who represent what its coordinator, Alfredo Romero, calls political prisoners.
In the complaint, it named some of the military commanders it said were in charge during the detentions, including Army Gen. Freddy Hernandez Parababi and Col. Edgardo Zuleta, Lt. Col. Rafael Quero Silva and Lt. Col. Henry Arellano Gallardo of the National Guard.
The rights group asked the ICC to request more information about the detentions from the Venezuelan government and to launch an investigation.
Attorney General Luisa Ortega Diaz has said authorities are investigating only two complaints of alleged mistreatment by police officers against detainees.