A Shia pilgrim weeps during a pilgrimage to a shrine - AP/File photo.

AWWAMIYA The street graffiti is so brazenly political in Saudi Arabia's Eastern Province that it hardly seems like Saudi Arabia at all, Reuters reports.

'Down with the government', 'Death to the traitors' read the messages on the walls of Awwamiya, a small town in the eastern region on the Gulf coast where most of the conservative Sunni state's Shia minority lives.

The fear of landing in jail would normally curb such talk, but right now the mood in the Shia region is more enflamed that normal.

Hundreds of Shias have staged protests in recent weeks as police searched in vain for firebrand preacher Nimr al-Nimr, who breached a taboo to suggest in a sermon that Shias could one day seek their own separate state.

The threat, which diplomats say is unprecedented since the 1979 Iranian revolution provoked anti-Saudi protests, followed clashes between the Sunni religious police and Shia pilgrims near the tomb of Prophet Mohammad in the city of Medina, in the western region of the vast desert state.

'Graffiti like this underscores the fact that moderate Shias are losing influence on public opinion,' said Nasrallah al-Faraj, a Shia from Awwamiya who is among hundreds who have signed a petition asking police to stop their search for Nimr.

'Nimr was only expressing what the majority here feels ... While the option of secession is not on the table, you cannot stop people from thinking about it,' he said.

Saudi officials say Shias make up less than 10 per cent of the population, although diplomats believe the figure is closer to 15 per cent. Most live in the Eastern Province of Saudi Arabia, an absolute monarchy that grants no political rights.

Shia leaders who went into exile after the 1979 protests returned to the country in the 1990s in a historic deal with the government. But many say the community has not reaped the dividends and complain of continued second class status in a state whose brand of Sunni Islam sees them as virtual heretics.

The rising influence of Shia Iran, after the 2003 Iraq invasion empowered its Iraq's Shia majority, has revived official fears that Shias could become a fifth column against the Saudi state, analysts say.

There could be disturbances in the Eastern Province if Iran is attacked by Israel or the United States over its nuclear programme. And they could become more vociferous over their status if Iran comes to a deal with Washington.

'What scares Saudi society as a whole is that they (Saudi Shias) are being used as a bridge for external forces, on the pretext of defending rights,' said Mohammed al-Zulfa, a Sunni member of the Shura Council, the kingdom's quasi-parliament.

Neglected region

The Shia region is visibly less affluent than other parts of Saudi Arabia, the world's largest oil exporter which has enjoyed huge oil revenues in recent years.

Roads are poorer, and schools and hospitals scarcer. Ironically, most of the oil fields are in the eastern region.

Shias say state oil giant Aramco, the province's largest employer, is no longer recruiting as many Shias as before.

Officials at the Interior Ministry and the governorate of the Eastern Province were unavailable for comment. The government says it has begun removing disparaging references to Shias in school textbooks.

Zulfa said Shias should travel further afield to find work, rather than sticking to their region.

'The average Saudi now looks for a job everywhere in the country ... I don't want the Shias to remain confined to one area,' Zulfa said. 'Without realising it, they are discriminating against other people's right for a job in the Eastern Province.'

Several Shia clerics and community leaders, including Sheikh Hassan al-Saffar, have tried to calm the situation down, issuing a statement rejecting Nimr's secession call.

'We reiterate our commitment to the unity of the beloved homeland and reject any ... threat to its unity or cohesion, standing as one behind our wise leadership,' they said after a meeting with Interior Minister Prince Nayef last month.

In Awwamiya, residents said the situation was beginning to calm down. 'Riot police have left. It's a lot better now,' said a young woman who declined to give her name.