An Iraqi soldier inspects the scene of a car bomb attack at a parking lot of Mahmoun University in Baghdad December 11, 2006.  [Reuters]

Baghdad - Two car bombs exploded within seconds of each other Tuesday on a main square in central Baghdad, killing at least 54 people and wounding more than 106, police said.

The coordinated attack in Tayaran Square happened at 7 a.m. and involved a bomb in a parked car and a car carrying a suicide bomber, Lt. Bilal Ali said.

He said at least 54 Iraqis, including seven policemen, were killed and 146 people wounded.

The bombs targeted a police patrol and a crowd of Iraqis gathering to apply for jobs as day laborers.

The blasts were about 30 yards apart and were followed by gunfire. It was not immediately clear who was shooting ? police or insurgents continuing the attack.

Iraqis gather on the square in the morning to wait for minibuses or private cars that stop by and hire them for the day as construction workers, cleaners or painters. They can buy breakfast at stands set up on the square.

The suicide car bomber appeared to drive into one of those crowds and set off his explosives as the nearby parked car bomb also went off, Ali said.

Burnt vehicles lie at the scene of a car bomb attack in a parking lot of Mahmoun University in Baghdad December 11, 2006. [Reuters]

Khalil Ibrahim, 41, a shop owner in the area, suffered shrapnel wounds to his head and back.

"In the first explosion, I saw people falling over, some of them blown apart. When the other bomb went off seconds later, it slammed me into a wall of my store and I fainted," he said from a local hospital.

The square is located near several government ministries and a bridge that crosses the Tigris River to the heavily fortified Green Zone, where Iraq's parliament and the U.S. and British embassies are located.

Not long after the attack, two other large explosions could be heard in the area ? one at 8:25 a.m. and the other at 8:40 a.m. ? but the cause of these blasts was not immediately known.