Bombs ripped through Sunni areas in Baghdad and surrounding areas Friday, killing at least 76 people in the deadliest day in Iraq in more than eight months. The major spike in sectarian bloodshed heightened fears the country could again be veering toward civil war.

The attacks followed two days of bombings targeting Shiites, including bus stops and outdoor markets, with a total of 130 people killed since Wednesday.

Scenes of bodies sprawled across a street outside a mosque and mourners killed during a funeral procession were reminiscent of some of the worst days of retaliatory warfare between the Islamic sects that peaked in 2006-2007 as U.S. forces battled extremists on both sides in the second Iraq war.

Tensions have been intensifying since Sunnis began protesting what they say is mistreatment at the hands of the Shiite-led government, including random detentions and neglect. The protests, which began in December, have largely been peaceful, but the number of attacks rose sharply after a deadly security crackdown on a Sunni protest camp in northern Iraq on April 23.

Majority Shiites control the levers of power in post-Saddam Hussein Iraq. Wishing to rebuild the nation rather than revert to open warfare, they have largely restrained their militias in the past five years or so as Sunni extremist groups such as al-Qaida have frequently targeted them with large-scale attacks.

Nobody claimed responsibility for Friday’s attacks, but the fact they occurred in mainly Sunni areas raised suspicion that Shiite militants were involved. The bombs also were largely planted in the areas, as opposed to the car bombings and suicide attacks that al-Qaida in Iraq and other Sunni insurgents are known to use.

Talal al-Zobaie, a Sunni lawmaker, called on politicians across the religious and ethnic spectrum to put aside their differences and focus on protecting the nation.

“The terrorist attacks on Sunni areas today and on Shiite areas in the past two days are an indication that some groups and regional countries are working hard to reignite the sectarian war in Iraq,” he said. “The government should admit that it has failed to secure the country and the people, and all security commanders should be replaced by efficient people who can really confront terrorism. Sectarianism that has bred armies of widows and orphans in the past is now trying to make a comeback in this country, and everybody should be aware of this.”

The areas hit Friday were all former Sunni insurgent strongholds that saw some of the fiercest fighting of the U.S.-led war as sectarian rivalries nearly tore the country apart.

The deadliest blast struck worshippers as they were leaving the main Sunni mosque in Baqouba, 35 miles northeast of Baghdad. Another explosion went off shortly afterward as people gathered to help the wounded, leaving 41 dead and 56 wounded, according to police and hospital officials.

A roadside bomb exploded later Friday during a Sunni funeral procession in Madain, about 12 miles south of Baghdad, killing eight mourners and wounding 11, police said. Two medical officials confirmed the casualties.

Another blast struck a cafe in Fallujah, 40 miles west of Baghdad, killing two people and wounding nine, according to police and hospital officials.

In Baghdad, a bomb exploded near a shopping center during the evening rush hour in the mainly Sunni neighborhood of Amariyah, killing 21 people and wounding 32. That was followed by another bomb in a commercial district in Dora, another Sunni neighborhood, which killed four people and wounded 22.