BAGHDAD — Market blasts and other bombings across Iraq killed at least 33 people and wounded nearly 100 on Tuesday, spooking an already-rattled public and spurring security officials to clamp down on traffic as Shiite Muslims brace for more tragedy during pilgrimages this week.

The wave of morning bombings struck four Iraqi cities, the worst hit being Diwaniyah, 130 kilometers (80 miles) south of Baghdad, where an explosives-laden vegetable truck detonated in a crowded market, killing 25 people and leaving 40 injured.

Vegetable seller Salah Abbas, 41, described a scene of chaos after the explosion ripped through the crowd.