(CNN) -- An opposition Shia Muslim party increased the number of parliamentary seats it holds in the Gulf kingdom of Bahrain in elections, results indicated Sunday.
The Islamic National Accord Association won all 18 seats it campaigned for in the 40-seat legislature of the Sunni-run kingdom, it said after polls closed Saturday. That's one more than it won in the last elections, in 2006.
The country's Justice Minister Khaled bin Ali Al-Khalifa announced the results on national television.
There will have to be run-off elections for nine seats, he said, with voting scheduled for next Saturday.
Bahrain's Muslim population is 65 to 75 percent Shia, the Pew Forum on Religion & Public Life estimated in a report on the global Muslim population.
But Sunnis -- who make up the vast majority of the world's Muslims -- dominate the government of the island kingdom.
The Islamic National Accord Association, locally known as al-Wefaq, campaigns for a greater say in the Gulf monarchy.
Saturday's elections were the third under the new constitution brought in by Sheikh Hamad bin Isa Al-Khalifa after he became king in 1999.
The constitution gave women the vote and created a two-chamber legislature -- one elected by the people and one appointed by the sheikh.
CNN's Amir Ahmed contributed to this report.