A truck bomb has exploded in a crowded market in southern Iraq, killing at least 25 people and wounding at least 50 others others.

The attack Tuesday happened in Diwaniya, about 150 kilometers south of Baghdad. Shortly after the blast, authorities declared a partial curfew in the city.

Earlier Tuesday, at least four people died when a pair of car bombs targeting Shi'ite pilgrims exploded near the central city of Karbala. The attack comes days ahead of ceremonies in Karbala to mark the birth of a key Shi'ite imam.

Violence in Iraq has increased in recent weeks, with attacks in June killing at least 237 people.