DUBAI, (Reuters) - Ebrahim Raisi’s record of fierce loyalty to Iran’s ruling clerics helped explain why the senior judge had been expected to win Friday’s presidential election, a contest the authorities limited almost exclusively to hardline candidates like him.

The win for Raisi, 60, an implacable critic of the West whose political patron is Supreme Leader Ayatollah Ali Khamenei, burnishes his chances of one day succeeding Khamenei at the pinnacle of power, analysts say.

Accused by critics of human rights abuses stretching back decades - allegations his defenders deny Raisi was appointed by Khamenei to the high-profile job of judiciary chief in 2019.

Later that year, Raisi headed the legal system as authorities used the courts to suppress the bloodiest political unrest since the 1979 Islamic revolution. Iran says its legal system is independent and not influenced by political interests.

“Raisi is a pillar of a system that jails, tortures, and kills people for daring to criticize state policies,” said Hadi Ghaemi, executive director of New York-based advocacy group the Center for Human Rights in Iran (CHRI), in a statement.

Iran denies it tortures prisoners. A mid-ranking figure in the hierarchy of Iran’s Shi’ite Muslim clergy, Raisi has been a senior judiciary official for most of his career. He served as deputy head of the judiciary for 10 years, before being appointed prosecutor-general in 2014.

Gaining a reputation as a feared security hawk, he was one of four judges who oversaw executions of thousands of political prisoners in 1988, rights. groups say. Amnesty International has put the number executed at around 5,000, saying in a 2018 report that “the real number could be higher”.

The CHRI said that those executed were “buried in unmarked mass and individual graves, based on the committee’s determination of their ‘loyalty’ to the newly established Islamic Republic. These prisoners had already been tried and were serving their issued prison sentences”.