Former Interior Minister Ousman Sonko is facing charges involving rape and torture in what is being called a "landmark trial" for universal jurisdiction prosecuting crimes against humanity.

Proceedings against Gambia's former Interior Minister Ousman Sonko for crimes against humanity began Monday in a Swiss federal court.

Sonko is accused of "having supported, participated in and failed to prevent systematic and generalized attacks as part of the repression carried out by the Gambian security forces against all opponents of the regime."

The crimes are alleged to have taken place over the course of 16 years, and include nine counts of crimes against humanity under Yahya Jammeh's dictatorship.

Who is Ousman Sonko?

Sonko was the West African nation's interior minister between 2006 and 2016, and has been held in Switzerland where he applied for asylum in 2017 after being sacked from his position.

Sonko was detained after Geneva-based NGO Trial International made a complaint.

The NGO posted on social media that in this "landmark trial," Sonko would be "the highest-ranking state official ever to be tried for international crimes" under the principle of universal jurisdiction.

According to Trial International, Swiss prosecutors have charged Sonko with "a range of heinous acts: the killings of a political opponent in 2000; acts of sexual violence between 2000 and 2002, as well as in 2005; involvement in torture and illegal detention related to a coup plot in 2006; and the murder of a politician in 2011."

Sonko denies all charges but faces life imprisonment if convicted.

Why is the trial being held in Switzerland?

The case is being heard at the Federal Criminal Court of Switzerland in the southern city of Bellinzona, with proceedings expected to last a month. A verdict is unlikely to be delivered before March.

The trial is taking place under the principle of "universal jurisdiction," which allows national courts in third countries to prosecute crimes against humanity, war crimes and genocide regardless of where the crimes were alleged to have been committed.

In November, a German court sentenced a former member of a Gambian death squad to life inprisonment.

The defendant, Bai Lowe, was found guilty of crimes against humanity, murder and attempted murder for his role as a driver for the so-called "Junglers." military unit.

Lowe was linked to the killing of AFP journalist Deyda Hydara.

kb/wmr (AFP, AP)