BAGHDAD, Iraq (AP) _ A car bomb exploded outside an Iraqi army base in central Baghdad on Wednesday, killing six soldiers and wounding 25, police said.

The blast occurred at a base that occupies the former Muthanna airport, which has been targeted by insurgents several times over the last year, police officer Salam Hashim Mahmoud said.

The explosion could be heard across the city, and a plume of black smoke billowed into the air after the attack.

Flames leapt from two vehicles set ablaze after the attack. Mahmoud said the vehicles were driving by at the time of the attack.

An Interior Ministry security official, Ayad Hadi al-Maliki, said 25 people were wounded in the attack, 15 of them civilians.