A car bomb ripped through a market in a poor Shiite Muslim neighborhood on the eastern outskirts of Baghdad at sunset Saturday, killing at least 30 people, police said.

In all, at least 52 people were killed or found dead throughout the country Saturday, victims of mounting sectarian killings promised by Abu Musab Zarqawi, the Jordanian leader of al Qaeda in Iraq, a radical movement made up predominantly of Sunni Muslims.

Police Maj. Falah Mhamadawi of the Interior Ministry said a parked car packed with explosives detonated in front of fruit and vegetable stands in the market at Nahrawan, a poor suburb heavily populated by Shiites located about 20 miles east of Baghdad. In addition to killing at least 30 people, the bomb wounded 38, Mhamadawi said.

The dead and injured were taken to Kindi hospital in Baghdad, where some of the wounded lay bleeding on the hospital grounds, screaming in pain. Several had lost limbs.

"I came with my brother Hamid, whose right leg was blown off below the knee," said Alaa Mohammed, outside the hospital. "I saw neighbors putting him in a truck, so I just jumped in with him."

Throughout Iraq, meanwhile, police reported finding 16 bodies. The victims had been blindfolded, bound hand and foot and shot. Two other people died in bombings and four more were killed in shootings.

Saturday's attacks came after three days of bombings and shootings in Baghdad and elsewhere in which more than 200 people were killed and 600 wounded. Iraqi and U.S. officials have attributed the spike in violence to efforts by insurgents to derail the Iraqi political process ahead of an Oct. 15 constitutional referendum.

Al Qaeda in Iraq said the bombing surge in Baghdad was revenge for a joint Iraqi-U.S. offensive against its stronghold in Tall Afar, a city near the Syrian border.

In the northern city of Mosul, coalition forces said they arrested two alleged leaders of al Qaeda in Iraq. The two -- identified as Taha Ibrahim Yasin Becher, whose alias is Abu Fatima, and Hamed Saeed Ismael Mustafa, also known as Abu Shahed -- allegedly headed the group's organization in Mosul, the country's third-largest city.

A statement said the arrests occurred Sept. 5. It also said Abu Fatima took over as al Qaeda's top-ranking operative in Mosul after one predecessor was captured in June and another was killed in August. He held the post for only 12 days, the statement said.

Near Abu Ghraib prison, about 20 miles west of the capital, a suicide car bombing wrecked three vehicles in a U.S. convoy Saturday, police said. Insurgents fired seven mortar shells at the jail and used grenades to damage three armored vehicles in another U.S. convoy in the area. The U.S. military issued no immediate casualty reports.

Iraqis walk through wreckage left by a car bomber who detonated his vehicle as worshipers left a mosque in Tuz Khormato, 130 miles north of Baghdad.