The United States on Tuesday, March 20 strongly condemned attacks in Iraq which killed at least 45 people and said they were a blatant bid by extremists to undermine progress by the Iraqi people, AFP reported.

"We strongly condemn the attacks on innocent civilians in Iraq," said White House spokesman Jay Carney, but said that violence was at historic lows and that Iraqi forces were capable of maintaining overall security.

A wave of attacks killed 45 people in more than a dozen Iraqi cities on Tuesday, the anniversary of the US-led invasion of the country and just days before Baghdad hosts a landmark Arab summit.

The violence, which left nearly 200 people wounded, bore the hallmarks of Al-Qaeda, which typically tries to launch coordinated nationwide mass-casualty bombing campaigns.

No group immediately claimed responsibility.