Men in southern Saudi Arabia and the largely Shia-populated Eastern Province have turned out in their thousands to vote in municipal elections.
Polling booths were full in many areas
Some voters queued from dawn on Thursday in the second stage of the country's landmark local elections.
"We're overjoyed," said Hasan Khater, 25, after taking a picture of his three brothers in front of a polling station.
Women were not allowed to vote, while half the members of local councils are to be elected and the rest appointed.
BBC correspondent Heba Saleh says Shias are hoping the election, though a limited exercise in democracy, will not be a wasted opportunity and will help end discrimination against them.
They have been watching Shia Muslims in neighbouring Iraq asserting their political power, our correspondent says.
The turnout was so high at one polling centre in the eastern city of Dammam that police were forced to close the gate because of overcrowding, reports said.
Some members of the crowd angrily accused officials of hindering voting, but candidates said the delay did not seem intentional.
"In the future, we hope to vote in parliamentary elections, God willing," said Sheikh Mohammad al-Taieb outside a polling centre in Qatif, where all five seats are expected to go to Shia candidates.
Voter registration has been a festive affair in parts of the province
"Shias have been marginalised for years ... Now Shia are starting to get their voice heard ... in this good country," Mr Taieb told the AFP news agency.
The Shia have long complained that they are excluded from most local and national government posts.
They also say they face restrictions on building their mosques and performing their religious rites.
In recent years, there has been a slight easing of restrictions in Qatif. Elsewhere, however, not much has changed.
Many influential Sunni clerics continue to view the Shia as heretics who practise pagan rites.
Crown Prince Abdullah has been careful to reach out to the Shia on occasion, but equality is probably still a long way in the future, our correspondent says.