A blistering string of apparently coordinated bombings and a shooting across Iraq killed at least 51 and wounded dozens Sunday, spreading fear throughout the country in a wave of violence that is raising the prospect of a return to widespread sectarian killing a decade after a U.S.-led invasion.

Violence has spiked sharply in Iraq in recent months, with the death toll rising to levels not seen since 2008. Nearly 2,000 have been killed since the start of April, including more than 180 this month.

The surge in bloodshed accompanies rising sectarian tensions within Iraq and growing concerns that its unrest is being fanned by the Syrian civil war raging next door.

One of the deadliest attacks came in the evening when a suicide bomber blew himself up inside a cafe packed with young people in the largely Shiite neighborhood of al-Ameen in southeastern Baghdad. The attack killed 11 and wounded 25, according to police.

Clothes shop owner Saif Hameed, 24, was watching TV at home when he heard the blast nearby. He saw several of the wounded being loaded into ambulances.

“It seems the terrorists are targeting any place they can, no matter what it is,” he said. “The main things for them are to kill as many Iraqis as they can and keep the people living in fear.”

Most of Sunday’s car bombs hit Shiite-majority areas and caused most of the casualties. The blasts hit half a dozen cities and towns in the south and center of the country.

There was no claim of responsibility for any of the attacks, but they bore the hallmark of al-Qaida in Iraq, which uses car bombs, suicide bombers and coordinated attacks, most aimed at security forces and members of Iraq’s Shiite majority.

The U.S. Embassy condemned the attacks, saying it stands with Iraqis “who seek to live in peace and who reject cowardly acts of terrorism such as this.” The U.S. withdrew its last combat troops from Iraq in December 2011, though a small number remain as an arm of the embassy to provide training and facilitate arms sales.

Sunday’s blasts began with a parked car bomb exploding early in the morning in the industrial area of the city of Kut, killing six people and wounding 15 others. That was followed by another car bomb outside the city that targeted construction workers. It killed five and wounded 12, according to police.

In a teahouse hit by one of the blasts, a blood-stained tribal headdress and slippers were strewn on the floor, alongside overturned chair and couches. Kut is 100 miles southeast of Baghdad.

In the oil-rich city of Basra in southern Iraq, a car bomb exploded on a busy downtown street. As police and rescuers rushed to the scene of the initial blast, a second car exploded. Six people were reported killed. Cleaners were seen sweeping up pieces of the car bomb, which damaged nearby cars and shops.

About an hour later, parked car bombs ripped through two neighborhoods in the southern city of Nasiriyah, 200 miles southeast of Baghdad, killing two and wounding 19, police said.

In the Shiite holy city of Najaf, 100 miles south of Baghdad, a blast struck a produce market, killing eight and wounding 28. Watermelons, tomatoes and apples were seen scattered on the ground. A bulldozer loaded charred and twisted stalls and cars into a waiting truck.