Baghdad:  Bomb blasts ripped through two popular pet markets in Baghdad on Friday, killing at least 72 people in the deadliest attacks in the city in six months and dealing a bitter blow to Iraqi hopes that security is getting better.

Police said a female suicide bomber killed 45 people and wounded 82 at the Gazil pet market in central Baghdad.

Another blast shortly after, caused by a second female suicide bomber, killed 27 people and wounded 67 at a bird market in southern Baghdad, they said.

An Iraq military spokesperson said the female bombers had Down's syndrome

The White House expressed its solidarity with Iraqis in the wake of the suicide bombings.

"These extremists have no regard for life. We will continue to stand with the Iraqi people to defeat these terrorists," said Gordon Johndroe, a White House spokesman.

The US ambassador to Iraq said the bombings show that a resilient Al Qaida has "found a different, deadly way" to try to destabilise Iraq.

Ambassador Ryan Crocker said "Al Qaida has been damaged, but ... it is still there, it is resilient and it is determined. Their car bomb capabilities have been badly disrupted so now, as we saw today and as we've seen for some time, they are moving toward suicide vests, in this case suicide vests worn by women."

At the Gazil market people stared at the destruction as workers swept up body parts and blood-stained animal boxes.

"I came here to enjoy myself. I don't know how I survived," said witness Abu Haider, who was covered in blood as he stood among ruined stalls and carcasses of birds and other animals.

One witness said the female bomber entered the market saying she had birds to sell. Scores of people gathered and then the bomb underneath her clothing went off, the witness said.

Major-General Qasim Moussawi, spokesman for the Iraqi military in Baghdad, said in both attacks women had been loaded with explosives which were then detonated remotely. "We found the mobiles used to detonate the women," he said.