Senior Muslim cleric Sheikh Youssef al-Qaradawi, who was based in Qatar and was a spiritual leader for the Muslim Brotherhood, died on Monday, according to a post on his official Twitter account.

The cleric, who was in his nineties, was highly critical of Egypt’s President Abdel Fatah al-Sisi.

Broadcast into millions of homes, his sermons fuelled tensions that led Saudi Arabia and its Gulf allies to impose a blockade on Qatar in 2017 and declare Qaradawi a terrorist.

his death was announced on his official Twitter account.

Qaradawi, who studied at Cairo’s Al-Azhar University, was often described by supporters as a moderate who offered a counterweight to the radical ideologies espoused by al-Qaeda. He strongly condemned the Sept. 11, 2001 attacks in the United States, and supported democratic politics.