The United Nations (UN) human rights chief has warned that the government of Venezuelan President Nicolas Maduro may move to further crush democratic institutions and that crimes against humanity may have already been committed by his security forces.

“My investigation suggests the possibility that crimes against humanity may have been committed, which can only be confirmed by a subsequent criminal investigation,” Zeid Ra'ad al Hussein told the UN Human Rights Council, which Venezuela's foreign minister was due to address later in the day.

Last month, Zeid's office said that Venezuela's security forces had committed extensive and apparently deliberate human rights violations in crushing anti-government protests and that democracy was “barely alive”.