RIYADH, Saudi Arabia (AP) — Saudi Arabia announced on Saturday it had executed 47 prisoners convicted of terrorism charges, including al-Qaida detainees and a prominent Shiite cleric who rallied protests against the government.

The execution of Sheikh Nimr al-Nimr is likely to deepen discontent and spark protests among Saudi Arabia’s Shiite minority, largely concentrated in the kingdom’s east. Protests may also erupt in neighboring Bahrain, which has seen low-level violence since 2011 protests by its Shiite majority demanding greater rights from its Sunni-led monarchy.

SANA'A, YEMEN - OCTOBER 18: Supporters of the Ansarullah Movement (Houthis) chant slogans to protest the death sentence given to Saudi Shia cleric Sheikh Nimr Baqir al-Nimr outside the embassy of Saudi Arabia in Sana'a, Yemen, on October 18, 2014. (Photo by Mohammed Hamoud/Anadolu Agency/Getty Images)

SANA’A, YEMEN – OCTOBER 18: Supporters of the Ansarullah Movement (Houthis) chant slogans to protest the death sentence given to Saudi Shia cleric Sheikh Nimr Baqir al-Nimr outside the embassy of Saudi Arabia in Sana’a, Yemen, on October 18, 2014. (Photo by Mohammed Hamoud/Anadolu Agency/Getty Images)

The execution of al-Qaida militants convicted over deadly bombings and shootings in Saudi Arabia raised concerns over revenge attacks. The extremist group’s branch in Yemen, known as al-Qaida in the Arabian Peninsula, warned Saudi security forces last month of violence if they carried out executions of members of the global network.

The Interior Ministry announced the names of the 47 people executed in a statement carried by the state-run Saudi Press Agency. Saudi state television also reported the executions.

Of those executed, 45 were Saudi citizens, one was from Chad and another was from Egypt.

One of the executed was Faris al-Shuwail, a leading ideologue in al-Qaida’s Saudi branch who was arrested in August 2004 during a massive crackdown on the group following a series of deadly attacks.

A Saudi lawyer in the eastern region of the kingdom told The Associated Press that al-Nimr was among at least four Shiite political detainees who were executed. The lawyer spoke on condition of anonymity for fear of reprisal.

Saudi Arabia said a royal court order was issued to implement the sentences after all appeals had been exhausted. The executions took place in the capital, Riyadh, and 12 other cities and towns, the Interior Ministry statement said. Nearly all executions carried out in Saudi Arabia are by beheading with a sword.

In a press conference Saturday, Interior Ministry spokesman Maj. Gen. Mansour al-Turki said the executions were carried out inside prisons and not in public.

In announcing the verdicts, Saudi state television showed mugshots of those executed. Al-Nimr was No. 46, expressionless with a gray beard, his head covered with the red-and-white scarf traditionally worn by men in the Arab Gulf region.

Al-Nimr, who was in his 50s, had been a vocal critic of Bahrain’s Sunni-led monarchy, which forcibly suppressed the 2011 Shiite-led protests with the help of Saudi troops.

In November, state-linked media had begun circulating unofficial reports that nearly 50 prisoners would be executed soon. Amnesty International warned that the execution of dozens of people in a single day “would mark a dizzying descent to yet another outrageous low.”

U.S.-based Human Rights Watch criticized the executions. Sarah Leah Whitson, the group’s Middle East director, said “regardless of the crimes allegedly committed, executing prisoners in mass only further stains Saudi Arabia’s troubling human rights record.”

She said al-Nimr was convicted in an “unfair” trial and that his execution “is only adding to the existing sectarian discord and unrest.”

“Saudi Arabia’s path to stability in the Eastern Province lies in ending systematic discrimination against Shia citizens, not in executions,” she said.

Before his arrest in 2012, al-Nimr had spoken out against the killing of protesters and other injustices, singling out the Sunni monarchy in Bahrain as well as the Syrian government, which is dominated by that country’s Alawite minority, an offshoot of Shiite Islam.

SANA'A, YEMEN - OCTOBER 18: A supporter of the Ansarullah Movement (Houthis) holds a portrait of Shia cleric Sheikh Nimr Baqir al-Nimr sentenced to death in Saudi Arabia during a demonstration outside the embassy of Saudi Arabia in Sana'a, Yemen, on October 18, 2014. (Photo by Mohammed Hamoud/Anadolu Agency/Getty Images)

SANA’A, YEMEN – OCTOBER 18: A supporter of the Ansarullah Movement (Houthis) holds a portrait of Shia cleric Sheikh Nimr Baqir al-Nimr sentenced to death in Saudi Arabia during a demonstration outside the embassy of Saudi Arabia in Sana’a, Yemen, on October 18, 2014. (Photo by Mohammed Hamoud/Anadolu Agency/Getty Images)

At his trial, he was asked if he disapproved of the Al Saud ruling family after speeches in which he spoke out forcefully against former Interior Minister and late Crown Prince Nayef bin Abdelaziz.

“If injustice stops against Shiites in the east, then (at that point) I can have a different opinion,” the cleric responded, according to his brother Mohammed, who attended court sessions and spoke to The Associated Press before the verdict.

Al-Nimr did not deny the political charges against him, but said he never carried weapons or called for violence.

Al-Nimr’s brother, Mohammed al-Nimr, wrote a series of comments on Twitter after the execution, expressing hope that “we will overcome sectarianism to be in a better position.”

“You are wrong, uncertain and mistaken if you think that killing will stop demands for rights. We remain peacefully demanding reform and change in our country,” he wrote.

His son Ali, the cleric’s nephew, is also facing execution, but his name was not among those listed Saturday. Amnesty International describes Ali al-Nimr as a juvenile offender because he was 17 years old in February 2012 when he was arrested. He was later convicted, and his death sentenced upheld, on charges of attacking security forces, taking part in protests, armed robbery and possessing a machine-gun.

In Lebanon, a top Shiite cleric condemned al-Nimr’s execution, describing it as “a grave mistake that could have been avoided with a royal amnesty that would have helped reduce sectarian tensions in the region.”

“We have warned the concerned sides that any such reckless act means a catastrophe for the nation,” said Sheikh Abdul-Amir Kabalan — deputy head of the influential Supreme Shiite Islamic Council, the main religious body for Lebanon’s 1.2 million Shiites.

“This is a crime at a human level and will have repercussions in the coming days,” he said in a statement released by his office.

After listing the names and images of those executed, Saudi state television showed black-and-white footage of previous terror attacks in the kingdom, one showing bodies in a mosque after an attack. Soft, traditional music played in the background.