An al-Qaeda-linked group has claimed responsibility for the twin suicide bombings in the heart of Baghdad that claimed at least 155 civilian lives and left more than 720 others injured.

The militant group known as the Islamic State of Iraq said in a statement posted on the Internet late Monday that its "martyrs... targeted the dens of infidelity."

The attack Sunday in the heart of the Iraqi capital struck the Justice Ministry and the Baghdad Provincial Administration. It was Iraq's deadliest attack in two years and it raised more concerns about the country's ability to protect itself as it prepares for the January parliamentary elections and the US military withdrawal.

The self-styled Islamic State of Iraq is one of a handful of Sunni Arab extremist groups responsible for numerous bombings and other attacks on civilian targets throughout Iraq. It is spearheading the insurgency against US troops and forces loyal to Prime Minister Nouri al-Maliki.

The Islamic State of Iraq is battling for the long-term control of central and western areas which it believes could break away from the Kurdish and Shia-dominated provinces once the coalition forces depart.

According to an analysis compiled by US intelligence agencies, the Islamic State of Iraq has ambitions to create a terrorist enclave in the Iraqi provinces of Baghdad, Anbar, Diyala, Salah al-Din, Nineveh, and parts of Babil.

MP/HGL