The United Nations' top human rights official is calling for the immediate release of Leopoldo Lopez and dozens of other jailed opponents of Venezuela's socialist government.

UN High Commissioner for Human Rights Zeid Raad al-Hussein met with Lopez's wife Friday in Geneva to discuss the situation of 69 people still detained following deadly unrest that rocked Venezuela earlier this year.

Zeid said in a statement Monday that "the prolonged and arbitrary detention of political opponents and protestors in Venezuela is causing more and more concern internationally." The veteran Jordanian diplomat said he's "extremely concerned about the current situation."

Lopez was arrested in February after speaking at a rally that saw activists clash with police. He's currently on trial on charges of inciting violence.