Baghdad (CNN) -- A car bomber who penetrated Baghdad's heavily fortified Green Zone this week was targeting the Iraqi prime minister, authorities said Saturday.
The attack Monday left two people dead and seven others injured in the Green Zone, which houses the nation's government offices as well as U.S. and other embassies.
Police said the blast occurred at an outdoor parking lot that belongs to the Iraqi parliament.
No more details were available immediately on whether lawmakers were among the casualties.
Initial inquiries revealed an attempt to kill Prime Minister Nuri al-Maliki, according to Major Gen. Qassim Atta, the Baghdad security operations manager.
The black car was loaded with explosives and had three ways to detonate: manual, electric and by cell phone, he said.
"The intelligence information we have indicates that the vehicle was supposed to enter the building and park there until the arrival of the prime minister," Atta said.
Terrorists confessed that the car bomb was targeting the prime minister when he visits parliament in an upcoming session, according to Atta, who did not name the group behind the attacks.
The prime minister was not there at the time of the attack, he said.
The attacker was in a black Dodge with 20 kg (44 lb) of explosives, and was driving toward parliament when security forces stopped him because he did not have a proper badge.
The driver parked at the parliament compound, where the car exploded.
The attack comes amid a U.S. military withdrawal from the Middle Eastern country.
All American troops are scheduled to be out by the end of the year. Iraqi security forces, including army and police officers, are to assume full responsibility after the withdrawal.
CNN's Hamdi Alkhshali contributed to this report