More than a dozen car bombs ripped through marketplaces, parking lots and rush-hour crowds in Iraq on Monday, killing at least 58 people and pushing the country’s death toll for July toward the 700 mark, officials said.

The blasts — 18 in all — are part of a wave of bloodshed that has swept the country since April, killing more than 3,000 people and worsening already strained ties between Iraq’s Sunni minority and the Shiite-led government. The scale and pace of the violence, unseen since the darkest days of the country’s insurgency, have fanned fears of a return to the widespread sectarian bloodletting that pushed Iraq to the brink of civil war after the 2003 U.S.-led invasion.

With two days left in July, the month’s death toll stands at 680, according to an Associated Press count. Most of those deaths have come during Ramadan, the Muslim holy month of dawn-to-dusk fasting that began July 10, making it Iraq’s bloodiest since 2007.

“Iraq is bleeding from random violence, which sadly reached record heights during the holy month of Ramadan,” said the acting U.N. envoy to Iraq, Gyorgy Busztin. He said the killings could push the country “back into sectarian strife,” and called for immediate and decisive action to stop the “senseless bloodshed.”

There was no immediate assertion of responsibility for Monday’s attacks, but the Interior Ministry blamed al-Qaeda’s Iraq branch and accused it of trying to widen the rift between Sunnis and Shiites.

Sunni extremist groups such as al-Qaeda’s Iraq branch, known as the Islamic State of Iraq and the Levant, frequently use coordinated blasts like those Monday to try to break Iraqis’ confidence in the Shiite-led government and stir sectarian tensions.

The U.S. Embassy in Baghdad condemned Monday’s attacks and stressed that the United States “stands firmly with Iraq in its fight against terrorism.”

Iraq’s violence escalated after an April crackdown by security forces on a Sunni protest camp in the northern town of Hawijah that killed 44 civilians and a member of the security forces, according to U.N. estimates. The bloodshed is linked to rising sectarian divisions between Iraq’s Sunnis and Shiites as well as friction between Arabs and Kurds, dampening hopes for a return to normality nearly two years after U.S. forces withdrew from the country.

Monday’s attacks stretched from Mosul in the north to Baghdad in central Iraq and Basra in the south.

— Associated Press