The Shia enclave of al-Qatif in Saudi Arabia's Eastern Province is a thorn in the side of the Sunni elite who rule the desert kingdom.
The best-known resident from the area may be Sheik Nimr al-Nimr, the populist dissident Shia cleric whom the Saudi government killed in January during a wave of mass executions.
The Shia Muslims chafe at what they consider their second-class status within oil-rich Saudi Arabia, and al-Qatif has been a hotbed of opposition – some of it troubling for the reigning House of Saud.
Al-Qatif featured prominently this past week in the running debate over whether Canada's sale of $15-billion in combat vehicles to Saudi Arabia will enable the Sunni-dominated country to perpetrate human-rights violations on civilians.
The Globe and Mail published footage from Shia activists in al-Qatif showing Riyadh's forces using armoured vehicles against civilians. The vehicles that were deployed are not Canadian-made, but they demonstrate the Saudis' proclivity to use such machines against their people.
The Saudis frequently cite terror threats when they go after the area's dissidents, some of whom are more militant than others.
Toby Matthiesen, a senior research fellow at the University of Oxford who has studied the Saudi Shiites, describes al-Qatif as an "area under lockdown" and in a perpetual state of emergency – not unlike some other parts of the Middle East.
Prof. Matthiesen says Westerners, foreign journalists and diplomats are discouraged from visiting al-Qatif. "As soon as you go there, you realize what is going on. … It's a kind of war zone. It's not the image Saudi Arabia wants to portray."
Reuters reported earlier this year that foreign media are permitted to visit al-Qatif only if they are accompanied by government officials, which Riyadh says is necessary to ensure the journalists' safety.
Adam Coogle, a Middle East researcher with Human Rights Watch, says what distinguishes al-Qatif from other parts of Saudi Arabia are the numerous police checkpoints – a way for authorities to check identification and keep tabs on movement. "They can tighten these checkpoints in a tense period … and bring in armoured vehicles and park them here," Mr. Coogle said.
Human Rights Watch says Shiites face discrimination in employment, the education system and the courts, and cannot build houses of worship outside designated enclaves. "Government-affiliated religious authorities continued to disparage Shia Islam in public statements and documents," the group said in a recent report.
Not surprisingly, the Shiites in al-Qatif and other enclaves in the country have a history of chafing at Saudi rule.
"The Shia, and their areas, are economically marginalized," Prof. Matthiesen said. "They are excluded from many sectors of the state so they have been unhappy with their position in Saudi Arabia. So they have rebelled for decades."
The arrest, and ultimate execution, of Sheik al-Nimr has further inflamed tensions between al-Qatif and Riyadh. The Shia cleric was an outspoken critic of the House of Saud, and had called for its removal and supported anti-government protests in the Eastern Province.
His trial and sentencing for "disobeying the ruler," "inciting sectarian strife" and "encouraging, leading and participating in demonstrations" reignited criticism of Saudi Arabia's justice system.
Human Rights Watch, citing figures from local activists, estimated recently that more than 200 people from Shia-majority towns and villages in the Eastern Province have gone to trial for alleged protest-related crimes since 2011.
Mr. Coogle said the trials he has studied are appalling. "I've analyzed eight full Saudi trials of people who were involved in Eastern Province uprising and protest-related activities," he said. "Every case I read, and the way the trial process occurred, was absolutely ludicrous. I mean it was a mockery of justice.
"In almost every single case, you had people who were ultimately convicted, and many of them sentenced to death, based solely on their confession that they [later] recanted in court and said they were tortured into giving."
Shia dissidents have become more militant in recent years, with some of them wielding guns or Molotov cocktails, after a harsh crackdown by the Saudis when al-Qatif fielded protests in concert with the Arab Spring uprisings across the Middle East in 2011.
Prof. Matthiesen said it is expected that some have moved toward militancy as the efforts of the latest generation to seek change have been met with gunfire.
"Is their cause just? I suppose most people would agree that it is," he said of the desire among Saudi Shia Muslims for their grievances to be addressed.
"Did some of them start to use weapons? Yes, they did. So it's not a purely peaceful demonstration because if you go out and demonstrate, you get shot at," he said.
"So you only do that so long. So then who is to blame?"
In any case, Prof. Matthiesen said, the militancy of some Shiites helps the Saudi government. "It gives them the most important argument to present to the Saudi people and the West: that it's dealing with an armed insurgency, armed by Iran, which has to be crushed at all costs."
The Sunni rulers could move to put Shia Saudis on an equal footing. But they don't, Prof. Matthiesen said.
And the Wahhabi clergy who hold such sway in Saudi Arabia regard the Shiites as heretics and the enemy.
Ultimately, the restive Shia population offers a benefit to Riyadh, Prof. Matthiesen said. "The Shia threat helps rally other Sunnis around the flag and it's in fact rather useful."