Authorities said 13 people were wounded in the morning blast in a parking lot where the car exploded near busloads of pilgrims on the outskirts of Karbala, a city 55 miles (90 kilometers) south of Baghdad.
A second bomb was discovered nearby and dismantled before it could explode, police said.
The police and hospital officials spoke on condition of anonymity because they were not authorized to release the information.
Monday’s attack followed a triple suicide bombing last week along two highways leading to Karbala that killed 56 and wounded at least 180 — most of them Shiite pilgrims.
Hundreds of thousands of pilgrims are expected to gather in Karbala Monday night to mark the end of Arbaeen, a 40-day mourning period to observe the 7th century death of the Imam Hussein, one of the Shiite sect’s most revered figures.
No group so far has claimed responsibility for last Thursday’s bombing, but suicide attacks are the trademark of the Islamic State of Iraq, an Al-Qaeda front group believed made up mostly of Sunni religious extremists.
Such groups have frequently targeted Shiite civilians, in part because of religious differences and because Shiite parties gained power after the 2003 US-led invasion toppled Saddam Hussein’s Sunni-dominated regime.
Since the end of Saddam’s rule, Shiite politicians have encouraged huge turnouts at religious rituals, which were banned under the former regime, as a demonstration of Shiite power.
Also Monday, police said two bombs in Baghdad killed an Iraqi Army intelligence officer and his driver and wounded eight bystanders in separate strikes that hit a Shiite and a Sunni neighborhood. Hospital officials in Baghdad confirmed the fatalities.
A roadside bomb exploded near Tikrit as Salahuddin provincial Gov. Ahmed Abdullah Al-Jubouri’s motorcade was driving by, wounding five of his bodyguards, said police spokesman Col. Hatam Akram. The governor was not hurt in the blast near Saddam Hussein’s hometown, some 80 miles (130 kilometers) north of Baghdad.
Violence has dropped dramatically in Iraq since the height of the war three years ago. But small-scale bombings and drive-by shootings still persist on a near daily basis.
