A car bomb exploded Wednesday near several restaurants in a Shiite neighborhood of northwest Baghdad, killing at least 34 people and injuring more than 70, police and hospital officials said.

No group claimed responsibility for the horrific blast but the style and location of the attack suggested it was carried out by Sunni extremists, such as al-Qaida in Iraq, in an apparent bid to rekindle sectarian warfare as the U.S. draws down forces in the capital.

The blast appeared timed for maximum civilian casualties, going off about 7 p.m. when many Baghdad residents take advantage of cooler evening temperatures for shopping and dining in outdoor kebab restaurants.

It was the first major car-bombing in the capital since May 6, when 15 people were killed at a produce market in south Baghdad. That followed a string of deadly bombings against Shiite targets in the Baghdad area.

Nearly 200 people were killed in major bombings in Baghdad alone last month.

That has raised concern about security in the capital ahead of a June 30 deadline for the U.S. to remove all combat forces from Baghdad and other Iraqi cities.

Police said the blast happened in Shula, a sprawling Shiite neighborhood which had been a stronghold of Shiite militias including the Mahdi Army during the height of sectarian fighting two years ago.

Police officials said 34 people were killed and 72 injured. An official at the Health Ministry put the death toll at 37.

The officials spoke on condition of anonymity because they were not authorized to speak to the media.

A witness who gave only his nickname Abu Ahmed, or "Father of Ahmed," said a small truck carrying vegetables parked near a restaurant at Sadrian Square and the driver disappeared. After five minutes, the car exploded, killing men, women and children.

"I helped transfer many injured persons, despite my wounds," said Abu Ahmed, who was injured by shrapnel in his hands. "I saw pools of blood everywhere. More than 10 cars were damaged near the scene."

U.S. troops are due to leave the cities under terms of the U.S.-Iraq security agreement which took effect Jan. 1. President Barack Obama plans to remove combat troops from the country by September 2010 with all U.S. forces out of Iraq by the end of 2011.

Under the agreement, Prime Minister Nouri al-Maliki could ask the U.S. to delay the cities pullout. However, the issue is politically sensitive in a country worn out by six years of war, and al-Maliki has insisted there will be no delay in the withdrawal schedule.

Also Wednesday, three U.S. soldiers were wounded in north Baghdad in a blast from a type of weapon which the U.S. military believes comes is manufactured in Iran and smuggled from Iran.

The U.S. military confirmed the attack and said the bomb was an explosively formed projectile, which hurls a fist-sized piece of copper through armored vehicles. Iran has denied providing such weapons.

On Tuesday, Pentagon spokesman Geoff Morrell said U.S. troops are still finding large numbers of Iranian-made weapons in Iraq, despite's Iran's denials.