GENEVA (Reuters) – Venezuela’s Supreme Court has progressively dismantled the rule of law, becoming an instrument of President Nicolas Maduro’s government in what amounts to a coup against the constitutional order, an international human rights group charged on Tuesday.

The International Commission of Jurists (ICJ) said the top court had undermined human rights and infringed the Constitution through a series of rulings since December 2015.

In two rulings in March 2017, the Supreme Court of Justice “effectively claimed legislative powers for itself, depriving the National Assembly of its Constitutional powers and granting sweeping arbitrary powers to the executive,” it said.

“These decisions amount to a coup d’état against the Constitutional order and have ushered in a new reign of arbitrary rule,” Sam Zarifi, ICJ Secretary General, said in a statement.

Judges on the Supreme Court are mainly from the ruling Socialist Party and/or former officials of the government of Maduro, the Geneva-based jurists’ group said.

Maduro denies accusations of a power grab, saying his actions – including the creation of an alternative constituent assembly that has granted itself lawmaking powers – are aimed at restoring peace after months of protests and violence.

Zarifi said the Supreme Court of Justice “has issued its decisions based on political considerations and ideological and party loyalties to the executive power”.

The ICJ report, “The Supreme Court of Justice: an instrument of executive power”, was issued on the sidelines of the U.N. Human Rights Council which began a three-week session on Monday.

U.N. human rights chief Zeid Ra’ad al-Hussein said on Monday that Venezuelan security forces may have committed crimes against humanity against protesters and called for an international investigation.

(Reporting by Stephanie Nebehay; Editing by Mark Trevelyan)