Al-Qaida militant group in Iraq on Friday claimed responsibility for the suicide bombing targeting a recruitment center in central Baghdad on Tuesday this week, which left at least 59 people killed.

In a statement posted on an Islamic website, the self-styled Islamic State of Iraq (ISI) said that the bomber's target was a " group of Shiite apostates who sold their faith for money to be a tool used in a war against Iraqi Sunnis."

The ISI also sneered the claim that Baghdad is secure as " farcical", boasting that their "fighters" can reach any target they want to attack.

Tuesday's bloody bombing took place when a suicide bomber heavily loaded with about 30 kg of explosives, detonated himself in a queue of recruit outside a recruitment center, leaving 59 people killed and 129 more wounded, making it the most bloodiest attack in recent weeks.

As the U.S.combat troops withdraw from Iraq, sporadic violence and waves of high-profile attacks are still common in Iraqi cities as part of recent deterioration in security which shaped a setback to the efforts of the Iraqi government to restore normalcy in the country more than five months after violence-torn Iraq held parliamentary elections on March 7.