BAGHDAD, Iraq  —  A bomb struck a small bus carrying people to work in a predominantly Shiite area in Baghdad on Sunday, killing seven passengers and wounding 15, police said.

The minivan was ferrying passengers from Baghdad's Bab al-Sharqi area to the central commercial district of Karradah when the explosion occurred at 8:15 a.m., shattering the windows of nearby stores.

The bomb was left in a bag by somebody who got off the bus, police said, giving the casualty toll.

• Visit FOXNews.com's Iraq Center for more in-depth coverage.

Sirens wailed as police and ambulances rushed to the area, and people pulled the badly burned bodies from the charred bus.

Faris Mahdi, who works at a cell phone store near the site of the blast, said he and his colleagues tried to help the victims.

"We had just arrived to open our shop when we heard the sound of a big explosion and saw a fire in a small bus," Mahdi, 36, said. "We ran because the ambulances hadn't arrived yet. We pulled out three charred bodies, and badly injured people were taken to the hospital by a pickup car."

About 45 minutes later, a parked car bomb exploded outside a restaurant in eastern Baghdad, killing one person and wounding five others, according to police.