Thousands of Shiites took to the streets of eastern Saudi Arabia early yesterday, witnesses said, marking a mo-urnful religious anniversary in the Sunni state with unprecedented freedom.

In the town of Seihat, close to the coastal Gulf city of Dhahran, witnesses said several thousand people beat their chests in a night-time Ashura procession, commemorating the martyrdom of Imam Hussain, grandson of the Prophet Mohammed (PBUH).

Participants estimated at least 2,000 people had joined the procession in Seihat but said many more could take part before the night was over.

They said similar marches were taking place in six or seven towns in eastern Saudi Arabia.

There was no independent confirmation of the numbers. "This is the first year it was this many people," said Mohammed Al Madan, a 36-year-old bank employee. "Last year it was just half (as many)."

He said police and residents had co-operated to seal off parts of the mainly Shiite town for the religious ceremony.

"This is what we need. We need only respect from the government, and we will return it." Red, green and black Shiite flags decked a central Seihat square where a reconstruction of the death of Imam Hussain and an art exhibition depicting his suffering stoked Shiite grief.

Hussain was killed more than 1,300 years ago in Karbala, in what is now Iraq, where Shiites are also enjoying new religious freedoms after years of repression under deposed dictator Saddam Hussain.

In Saudi Arabia, home to Islam's two holiest sites and an austere Wahhabi school of Islam, Shiites have for years complained of second-class treatment. But they say authorities have eased restrictions on their ceremonies in recent years, particularly in the last 12 months.

"This year and last year there has been more freedom. Even last year the route of our procession was shorter - around half a kilometre or less. Now it's longer," said Hussain, a telecoms technician in the state oil firm Aramco.

Police had also set up security road blocks on the approaches to the town to thwart any potential attacks.

Saudi Arabia is battling a wave of militant violence. Attacks have so far targeted foreigners but militant sheikhs have in the past threatened action against Shiites. Shiites form around 10 per cent of Saudi Arabia's 24 million population. In the oil-rich Eastern Province they are believed to be a majority.

Along with easing restrictions on their religious rituals, the community members say they have begun to find a voice through the "national dialogue" instituted last year by Crown Prince Abdullah.

Participants to the dialogue, which included Sunni and Shiite scholars and academics, explicitly acknowledged the diversity of Muslim thought in the kingdom.