Al-Qaeda said in a statement that it had stormed the high-security jails after months of preparation.

Monday's attacks came exactly a year after the leader of al Qaeda's Iraqi branch, Abu Bakr al-Baghdadi, launched a "Breaking the Walls" campaign that made freeing its imprisoned members a top priority, the group said in a statement.

Al-Qaede militants have in recent months been regaining momentum in their insurgency against Iraq's government.

The group said it had deployed suicide attackers, rockets, and 12 car bombs, killing 120 Iraqi guards and SWAT forces in the attacks in Taji and Abu Ghraib, the prison made notorious a decade ago by photographs showing abuse of prisoners by US troops.

Sectarian tensions across the region have been inflamed and the violence has raised fears of a return to full-blown conflict.

Some politicians said the prison assaults showed the government was losing its grip on security.

So far in July, almost 700 people have been killed in militant attacks, according to violence monitoring group Iraq Body Count.

NJF/NJF