BAGHDAD (Reuters) -- Two car bombs exploded in central Baghdad and a suicide bomber blew himself up among police and civilians who rushed to help the wounded, a triple strike that killed 28 people and wounded 68.
In another attack, in Ba'qubah, capital of volatile northern Diyala Province, a teenaged girl in a suicide bomb vest blew herself up at a checkpoint of U.S.-backed security patrolmen, killing four people and wounding 18.
Police said the bomber was a girl of 13.
The triple attack in Baghdad, one of the deadliest incidents in Iraq for months, took place in the Kasra neighborhood on the east bank of the Tigris River in a bustling area of tea shops and restaurants near a fine arts institute.
Male and female students, many of whom were having breakfast at the time of the strike, were among the dead and wounded, as were Iraqi soldiers and police who had rushed to the scene.
A Reuters television crew filmed scenes of massive devastation, with street-front restaurants filled with rubble and cars reduced to twisted steel.
Such coordinated and massive strikes have become rare but steady reminders of the capacity of militants to unleash mayhem in Iraq, even though they no longer control whole swathes of towns and villages and violence overall has fallen sharply.
The attack by a female suicide bomber in Baquba is part of a trend that has increased this year. U.S. forces say Al-Qaeda Sunni Islamist militants are increasingly recruiting female bombers -- often teenaged girls -- to thwart security checks.
Many of the female bombers have lost male relatives and are seen as psychologically vulnerable to recruitment for suicide missions.
Al-Qaeda and like-minded groups have been driven out of many parts of Iraq after local Sunni Arab tribesmen turned against them, but they are making a stand in northern areas such as the rural groves near Baquba.
They often target the mainly Sunni U.S.-backed security patrols, whom they call collaborators.