A Malian terrorist accused of being central to the “persecution” of residents of Timbuktu and the destruction of the city's holy grounds refused to enter a plea Tuesday as his lawyers argued he was not mentally fit to stand trial.

Prosecutors at the International Criminal Court, which opened the trial on Tuesday, say the Ansar Dine terrorist group that al-Hassan Ag Abdoul Aziz belonged to control every aspect of public life in Timbuktu after seizing part of the north of Mali in 2012 along with Tuareg separatists.

Timbuktu's inhabitants were “belittled, humiliated and assaulted, subject to a veritable persecution on religious and gender grounds to which they saw no end and in which al-Hassan, the acting embodiment of the Islamic police, played a leading role,” ICC prosecutor Fatou Bensouda told judges.

As well as trying to impose sharia Islamic law across divided Mali, the al Qaeda-linked fighters used pick-axes, shovels and hammers to shatter earthen tombs and centuries-old shrines reflecting the local Sufi version of Islam in what is known as the “City of 333 Saints.”

This kind of Sufi worship was anathema to Islamists like the Ansar Dine fighters who adhere to a puritanical branch of Sunni Islam.

The attacks, which drew international condemnation, were an echo of the 2001 dynamiting by the Taliban of two 6th-century statues of Buddha carved into a cliff in Bamiyan in Afghanistan.

The ICC, the world's only permanent war crimes tribunal, has been examining events in Mali since 2012. French and Malian troops pushed the rebels back the following year.

Al-Hassan faces 13 charges for rape, torture, sexual slavery and directing attacks against religious and historical buildings.

According to his defense team, restrictions related to the coronavirus outbreak meant they had not been able to see their client in person for four months. He has been held in ICC custody since March 2018.

When they finally did this month they were “alarmed” at his state and cited a defense health expert report that al-Hassan was “experiencing disassociation” due to post-traumatic stress from “severe maltreatment” he suffered earlier while in jail in Mali before his transfer to The Hague.

While the judges ordered a medical examination of al-Hassan to determine his fitness to stand trial, they also ruled they would not delay the hearing.

Al-Hassan was asked to enter a plea to each of the charges but refused, telling judges 13 times: “I cannot answer that question.”

He is the second suspect from Mali to appear before the ICC over crimes suspected to have been committed by Ansar Dine. Ahmad al-Faqi al-Mahdi pleaded guilty to the destruction of cultural heritage for his part in smashing the mausoleums. He was sentenced to nine years in 2017 after apologizing for his actions.