The fact that the bomber was able to make it through not one but two checkpoints before exploding, casts doubt on the abilities of Iraq's security forces as US forces prepare to pull out by the end of August.

The bomber was apparently waved through two army checkpoints leading to the station's office along a narrow street after security guards checked his identification, said Iraqi military spokesman Maj. Gen. Qassim Al-Moussawi.

The explosion occurred about 10 minutes after the bomber cleared the second checkpoint.

“This has the clear fingerprints of Al-Qaeda,” Al-Moussawi told the channel. No one has yet claimed responsibility for the blast, but Al-Moussawi said documents had been found indicating Al-Qaeda was planning to target Arabic news channels and other media offices in the country.

Members of the channel's security department were arrested, Al-Moussawi added without elaborating.

A man who lives next door questioned how the bomber could have gotten so close. “What can we say? There are checkpoints. What are they doing?” said the man, whose shirt was speckled with blood.

He declined to give his name fearing retaliation, but said many members of his family were injured in the attack.

The massive blast blew out windows in the two-story Al Arabiya building and left much of the interior in shambles, with doors hanging off their frames. Three guards, a driver, a passer-by and a 50-year-old cleaner died in the blast in front of the building. Former Deputy Prime Minister Salam Al-Zubaie, who lives nearby, was rescued from under the rubble of his home and underwent surgery.