Baghdad, Iraq ? Two car bombs exploded in central Baghdad this morning, killing at least 54 people and wounding more than 140, 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.

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.

On Monday, at least 66 more people were killed or found dead in the Baghdad area and northern Iraq. They included 46 men who were bound, blindfolded and shot to death in Baghdad – the latest apparent victims of sectarian death squads.