An African Union-backed court in Senegal forced former Chadian President Hissene Habre to appear for the start of his trial on on charges of crimes against humanity on Monday, after he denied the legitimacy of the tribunal.

Habre, dressed all in white, was taken into the courtroom before the media were allowed to enter and seated in front of the judges’ dais.

“Habre was brought in by force,” said a source close to the special court.

Habre is accused of being responsible for the torture and killing of thousands of people during his 1982-1990 rule in his central African country.

“Down with imperialism,” Habre shouted before the start of the trial, a cry which was taken up by his supporters seated in the court. He was rushed from the courtroom by security men.

The trial marks the end of a 15-year battle to bring him to justice in Senegal, where he has lived in exile after being toppled in a coup.

“This is the end of a nightmare and we are moved by a sense of pride,” said Jacqueline Moudeina, lead lawyer for the victims, seated on a bench some 20 metres (66 ft) behind Habre.

“The presence of Habre is therapy for his victims,” Moudeina said. “The fact that he is here and listens to victims speak of all the atrocities they suffered is already a great victory.”

A lawyer close to Habre said he would not address the tribunal and refused to recognise its authority. Members of Habre’s family were in the courtroom but refused to speak to journalists.

The trial marks the first time that a court in one country anywhere in the world has prosecuted the former ruler of another on rights charges, according to Human Rights Watch, which has played a leading role in supporting the victims’ case.

The proceedings, due to last around 3 months, are being heard by a Special African Chamber (CAE) created in 2013 by Senegal and the African Union. Habre faces charges of war crimes, torture and crimes against humanity.