BAGHDAD — A car bomb exploded on a bustling commercial street in western Baghdad’s Shiite district of Hurriya yesterday, killing at least 51 people and wounding 75, security officials said.

The blast, which occurred at about 5:45 p.m., devastated a pleasant shopping area and bus stop where residents had waited for mini-bus taxis and vendors sold falafel, burgers, and juices. Rescuers lifted out the wounded and dead, while relatives searched for loved ones after the deadliest such attack in Baghdad since March.

A 14-year-old girl, dressed in a black headdress and robe, towed a boy in hand and searched for her father.

“Where are they going to take the injured?” she said in tears to other distraught pedestrians.

Bombs explode regularly in the capital, but deaths now seldom reach double digit figures. A pair of suicide bombings at pet markets in Shiite sections of Baghdad in February killed 99 people, and a double bombing in the city’s Karrada district killed 68 a month later.

Flames swallowed up a pair of power generators yesterday and shot up a three-story building, trapping the people inside and spewing a sheet of black smoke. The people inside climbed to the roof and ran across the other rooftops to escape. On the ground, a woman’s charred body lay in a car while volunteers carried wounded and dead from the carnage.

Some residents shaken by the blast blamed the Iraqi government and faulted them for weakening the Shiite cleric Moqtada al-Sadr’s Mahdi Army. The district, once mixed, became largely Shiite during the fall of 2006 when the capital was ripped by war and includes many of Mr. Sadr’s followers.

Mr. Sadr’s fighters carried out many reprisal attacks against Sunnis at the height of Iraq’s sectarian conflict, when car bombs exploded regularly in Shiite districts, killing dozens. However, the movement now has strained relations with Prime Minister al-Maliki, whom it faults for cooperating with the Americans and collaborating with their own political rival the Supreme Islamic Iraqi Council.