A prominent Shia cleric has been sentenced to death by a court in Saudi Arabia, his brother has revealed.

Sheik Nimr al-Nimr’s brother, Mohammed al-Nimr, announced the verdict on Twitter. He also wrote that the family would release a statement with more details.

Shia activist Jafar al-Shayeb said the verdict appears to have been handed down for criminal offences over the “incitement” of Shia protests in Saudi Arabia and neighbouring Bahrain.

He raised concerns that the death sentence of the revered 54-year-old cleric will spark anger and renewed protests by the kingdom’s minority Shias.

The cleric had faced charges that also include disobeying the ruler, firing on security forces, sowing discord, undermining national unity and interfering in the affairs of a “sisterly nation”.

A statement by the cleric’s family described the verdict as discretionary, suggesting that what the court found al-Nimr guilty of could have been eligible for a lighter sentence.

The family said the verdict sets a “dangerous precedent for decades to come”.

Prosecutors asked for execution followed by crucifixion. In Saudi Arabia, most death sentences are carried out by beheading. Crucifixion in this context means the body and head would then be put on display as a warning to others.

Al-Nimr had not denied the political charges against him, but denied ever carrying weapons or calling for violence. He can appeal the sentence.

Mr al-Shayeb said: “There’s a big chance there will be a reaction. There could be protests, marches, statements of condemnation. The situation is tense.”

Bahraini authorities painted over pictures of al-Nimr that had been plastered on walls by Shia supporters there.

Al-Nimr was a key leader of Shia protests demanding equal rights in 2011. Protests are banned in Saudi Arabia, where many ultraconservatives view Shias as heretics.

He also openly criticised the Sunni government of Bahrain’s handling of Shia protests there. Saudi Arabia sent troops to help Bahrain’s Sunni monarchy quell its Shia uprising in the tiny island nation.

Al-Nimr was arrested in July 2012 when he was shot by security forces in Saudi Arabia’s Eastern Province. Four security officers said he had weapons and fired on them first, prosecutors said.

Defence lawyers did not cross-examine security forces because they were not at the hearing they testified in. The lawyers said they were not told of the hearing.

According to Human Rights Watch, more than 1,040 people were detained in Shia protests between February 2011 and August 2014. There are at least 280 still imprisoned.

Human Rights Watch Middle East researcher Adam Coogle said: “I think the message that Saudis are saying is: ‘We will arrest anybody. We don’t care how high profile they are. Nobody is above this. We don’t have any tolerance. We don’t have any flexibility’.”

Mr Coogle said fears about Iran, the Middle East’s dominant Shia power, also played into the trial. He said that Saudi authorities view what happened in Bahrain and the Eastern Province of the kingdom as “meddling” by Iran.

“Talking up the Iranian threat is also an excuse to perpetuate systematic discrimination against Shia citizens,” he said.