BAGHDAD: Protesters clashed Friday with Iraqi police trying to prevent them from reaching the most venerated Sunni mosque in Baghdad, as violence killed eight soldiers and four militants in separate events.

In a weekly ritual, Sunnis once again massed for anti-government rallies in several Iraqi cities.

Iraqi security forces prevented worshippers from holding Friday prayers at the Abu Hanifa mosque last week as well, a development that reflects heightened sectarian tensions nearly a decade after the U.S. invasion of Iraq.

Police officials said anti-riot police used batons and water hoses in order to prevent worshippers from crossing a bridge leading to the mosque, which is located in the primarily Sunni neighborhood of Azamiyah.

The officials said five worshippers sustained bruises and minor injuries in the skirmishes at the bridge, about 2 km from Abu Hanifa. They spoke on condition of anonymity because they were not authorized to talk to the media.

Abdel-Rahman al-Azzawi was among a group of people who tried to cross the 14th of Ramadan bridge when they were met by security forces.

“We were showered with water and the policemen started to beat us,” Azzawi said.

“I do not know the reason behind this savage attack. We were only going to a mosque, not to Maliki’s office in the Green Zone,” he added, referring to the heavily secured quarter in the center of Baghdad where many officials have their offices.

The clashes did not reach the Abu Hanifa mosque itself. The area around the holy site was calm and hundreds of people, including Sunni parliament speaker Osama al-Nujaifi, attended the Friday prayers there.

During the Friday sermon in Abu Hanifa, Sunni preacher Ahmad Haasan al-Taha criticized the restriction of movement imposed on worshippers.

“Several days ago, the authorities promised us that they would provide the people free access to Abu Hanifa, but once again the government officials failed to live to their promises,” Taha said.

In the western province of Anbar, the heart of the protest movement that began in December, masked men arrived at the site of demonstrations in Fallujah raising the flag used by predominantly Sunni rebels in neighboring Syria.

They also held aloft a homemade black banner flag very similar to that used by Al-Qaeda’s branch in Iraq, suggesting supporters of the terror group are trying to make their presence felt in the largely peaceful Sunni protests.

The protests in Sunni areas were sparked by the arrest of bodyguards assigned to Finance Minister Rafia al-Issawi in late December.

Sunni protesters complain they suffer from discrimination by the Shiite-led government.

On Friday evening, gunmen shot dead eight Iraqi soldiers as they were on their way to report to their unit in a town north of Baghdad, security and medical officials said.

At least one soldier survived the gun attack in which the minibus the troops were traveling in overturned, but he was badly wounded, an Iraqi army colonel and a police colonel said. A doctor at the nearest hospital confirmed the toll. All three spoke on condition of anonymity.

The soldiers had set off from the town of Qaiyarah in the northern province of Nineveh, and were headed for a military camp in Taji 25 km north of the capital.

The gunmen opened fire on the minibus near the town of Baiji, about halfway between the two towns, causing the vehicle to overturn, at which point they opened fire on the soldiers.

The attackers fled the scene before emergency services arrived.

Earlier in the day, gunmen in the city of Baqouba broke into the house of Khalil Mohammad, a local leader in the Sahwa anti-Al-Qaeda movement, and killed him along with three of his sons, said police and hospital officials.

Baqouba is about 60 km northeast of the capital Baghdad.

The pro-government Sunni militiamen, known as Sahwa group, joined forces with U.S. troops to fight Al-Qaeda during the Iraq war. Since then, the group has been a target for Sunni insurgents who consider its members to be traitors.

The gunmen bound their hands and killed Khalil Mohammad and one of his sons in the house near Baqouba, a police lieutenant colonel said, adding the other two tried to escape but were killed in a nearby field.

A doctor from Baqouba General Hospital confirmed the toll.

Counting the latest attack, 17 members of the Sahwa anti-Al-Qaeda militia forces have been killed in violence this month.

The Sahwa are made up of Sunni Arab tribesmen who joined forces with the U.S. military against Al-Qaeda in late 2006, helping turn the tide against the insurgency.

The violence comes after a new study released Friday estimated that the conflict in Iraq had cost the lives of at least 116,000 civilians and more than 4,800 coalition troops between the outbreak of war in 2003 and the American withdrawal in 2011.

The report, published in the British peer-reviewed journal The Lancet, also estimated that the United States’ involvement in Iraq had so far cost it $810 billion and could eventually reach $3 trillion.