United Nations Secretary General Ban Ki-moon says he is “deeply dismayed” by Saudi Arabia’s execution of prominent Shia cleric, Sheikh Nimr al-Nimr, calling on the Riyadh regime to commute all death sentences handed down in the kingdom.

“Sheikh Nimr and a number of the other prisoners executed had been convicted following trials that raised serious concerns over the nature of the charges and the fairness of the process,” Ban’s spokesman quoted him as saying in a statement released on Saturday.

Earlier in the day, the Saudi Interior Ministry announced that Sheikh Nimr along with 46 others, who were convicted of being involved in “terrorism” and adopting a “Takfiri” ideology, had been put to death.

The UN chief had raised the case of Sheikh Nimr with Saudi leaders on several occasions, the statement read, reiterating Ban’s stance against the death penalty and urging the kingdom to commute capital punishment. 

In October 2015, Ban had called on the Al Saud regime to revoke Sheikh Nimr’s death sentence.

He called for “calm and restraint” in the face of the execution in a bid to avoid the exacerbation of strife in the region, according to the statement.

Sheikh Nimr, a critic of the Riyadh regime, was arrested in 2012 in the Qatif region of Shia-dominated Eastern Province, which was the scene of peaceful anti-regime demonstrations at the time.

He was charged with instigating unrest and undermining the kingdom’s security, making anti-government speeches and defending political prisoners. He had rejected all the charges as baseless.

In 2014, a Saudi court sentenced Sheikh Nimr to death, provoking widespread global condemnations. A year later, the sentence was upheld by the appeal court of Saudi Arabia.

The religious figure’s execution has drawn angry reactions worldwide. Widespread protest rallies have been held across the world to condemn the killing.

Saudi authorities also refused to hand over the cleric’s body to his family and buried him at an undisclosed cemetery, according to the Sheikh’s brother, Mohamed Nimr.