Sunni discontent has mounted after a bloody April raid by security forces on a protest camp in country's north. Violence has since spiked, claiming at least 5,500 lives according to the United Nations figures, although overall death tolls are still lower than at the height of the conflict in 2004-2008.
The bloodiest attacks, including waves of coordinated car bombs claimed by al-Qaida's local branch, have targeted mainly Shiites. But Sunnis have also been killed in apparent reprisals.
On Friday, bombs targeted two Sunni mosques in Baghdad, killing four. And last week, gunmen killed a cleric as he was leaving a mosque in western Baghdad, police said.
The mosque closures were "prompted by the systematic targeting of and injustice against Sunni clerics, mosques and worshippers," al-Bayati told The Associated Press. "Today, it is not forbidden to shed Sunni blood ... For 11 months we have been saying peacefully that we are facing injustice but the government closes its ears," he said.
He didn't accuse any group of being behind the attacks, but said "the weakness of the security forces is exploited by (Shiite) militias."