An independent U.N. human rights expert has denounced Saudi Arabia's closed-door trials of suspects in the slaying of journalist Jamal Khashoggi and called on the kingdom to name the defendants.

Agnes Callamard, the special rapporteur on extrajudicial executions mandated by the U.N.-backed Human Rights Council, also put an onus on the five permanent U.N. Security Council countries.

Callamard said in a statement Thursday that the Saudi government invited representatives from the five countries to attend some court hearings.

She says China, France, Britain, Russia and the United States "risk being participants in a potential miscarriage of justice" and could be "complicit" if the trials turn out to involve violations of human rights law.

Callamard is leading a human rights probe into the Khashoggi's killing at the Saudi consulate in Istanbul in October.