A Saudi court has sentenced prominent Shia cleric Nimr al-Nimr to death after convicting the anti-government protest leader of "sedition", his brother and lawyer said.
The verdict risks a further escalation of tension with Saudi Arabia's minority Shia community.
Nimr, a driving force behind 2011 protests against Saudi Arabia's Sunni authorities in the Eastern Province, was also convicted of seeking "foreign meddling" in the country, a reference to Iran, his brother Mohammed al-Nimr wrote on Twitter.
The court also found Nimr guilty of "disobeying" the kingdom's rulers and taking up arms against security forces, his brother said.
Nimr, who is in his 50s, had been on trial since March 2013.
Most of Saudi Arabia's estimated two million Shias live in the east, where the vast majority of the wealthy kingdom's oil reserves lie, and many complain of marginalisation.
They began demonstrating in February 2011 after an outbreak of violence between Shia pilgrims and religious police in the Muslim holy city of Medina in western Saudi Arabia.
Protests escalated after the kingdom's intervention in neighbouring Bahrain to support that Shia-majority country's Sunni monarchy.
Tension increased in July 2012 when security forces wounded and arrested Nimr.
Clashes have now killed about 24 people, including at least four policemen.
In June this year, a court sentenced two people to death for "taking part in forming a terrorist group" and other crimes linked to the protests by Shias.
Several others have received multi-year jail sentences.
Speaking in November 2011, after four Shia were shot dead in Eastern Province, Nimr had demanded the "release of all those detained in the protests, and all prisoners of conscience - Sunnis and Shias."
In a speech at the funeral of one of the protesters, Nimr said: "We are determined to demand our legitimate rights by peaceful means."
In August 2012, seven Shia dignitaries from the community of Qatif in Eastern Province hailed a call by King Abdullah for the creation of a centre for Sunni-Shia interfaith dialogue.
But tension has continued to simmer.
Police said on 30 September that one of their officers was wounded when gunmen opened fire on a checkpoint in the Shia village of Awamiya.
Two days earlier a suspect was shot and killed during a firefight with police in the same village.
