Mahdi, aged 84, had been hospitalised in the United Arab Emirates three weeks ago.

His moderate Umma Party was one of the largest opposition parties under Bashir, and Mahdi remained an influential figure even after Bashir was toppled in April 2019.

Sudan’s transitional administration, which governs under a power sharing deal between the military and civilian groups, declared three days of mourning.

Last month, Mahdi’s family said he had tested positive for COVID-19. He was transferred to the UAE for treatment a few days later following a brief hospitalisation in Sudan.

In a statement, the Umma Party said Mahdi would be buried on Friday morning in the city of Omdurman in Sudan.

Mahdi had returned to Sudan in December 2018, following a year-long self-exile, just as protests over worsening economic conditions and Bashir’s rule gathered steam. His daughter Mariam Sadiq al-Mahdi, deputy leader of the Umma Party, was among those detained during the demonstrations.

While a successor to the party head has not yet been announced, she has been the most visible party leader in political negotiations and the media in recent years.

Opposition parties were weakened greatly under Bashir’s three-decade rule and are jostling for power with the military during Sudan’s transition, making the Umma Party’s continued unity crucial to maintaining the balance of power.

After the military overthrew Bashir, Mahdi pushed for a transfer to civilian rule. (Reporting by Khalid Abdelaziz and Hesham Abdul Khalek, Editing by Angus MacSwan)