After a one-day lull, bloodshed surged again in the capital Saturday, with at least 17 people dead in attacks and 27 probable victims of sectarian killings found dumped in the streets as Iraq's prime minister launched a fresh appeal for reconciliation.

Violence has escalated sharply in Baghdad over the past week, except for Friday, when only three killings were recorded — two Iraqis shot to death and a U.S. soldier killed by a bomb.

Saturday's toll raised the city's violent deaths to more than 180 just since Wednesday — either slain by bombs and gunfire or tortured and shot before being dumped, a hallmark of reprisal killings being waged between Shiite and Sunni Muslims.

CountryWatch: Iraq

Appealing again to Iraq's divided sects, Shiite Prime Minister Nouri al-Maliki urged Iraqis to put aside their sectarian, ethnic and political differences and embrace his reconciliation plan.

"National reconciliation is a correct way of thinking and carries a high feeling of responsibility," al-Maliki said. "To succeed in this today, we have to embrace the culture of dialogue and reconciliation."

Al-Maliki's plan is intended to bridge the communal animosities fueling Iraq's violence. Among its 24 points, it offers amnesty to members of the Sunni Arab-led insurgency not involved in terrorist activities and calls for disarming primarily Shiite sectarian militias.

But no major Sunni insurgent group has publicly agreed to join the plan, and no steps have been taken to rein in Shiite militias. Since the plan was unveiled in late June, car bombings, mortar attacks and shootings have killed hundreds of Iraqis.

Al-Maliki said that once the plan managed to create an "atmosphere of reconciliation and dialogue," his government would take steps based on the views expressed both by non-governmental groups and by tribal leaders — who last month agreed to back his effort.

"These decisions will be historic and they should be shouldered by all the groups participating in the political process," he said.

The U.S. military confirmed that Iraqi security forces plan to dig trenches and set up berms around Baghdad in an attempt to prevent insurgents and explosive-laden cars from getting into Baghdad.

"There is a plan in progress for a security belt around Baghdad that includes trenches and other obstacles for channeling exit from and entry to the city through checkpoints controlled by Iraqi forces. This is a cooperative effort between the Iraqi government and the coalition," said Lt. Col. Barry Johnson, a military spokesman.

In Saturday's violence, gunmen killed the former spokesman of a defunct political coalition that included Shiite, Sunni, Kurdish and independent parties. Mohammed Shihab al-Dulaimi was shot in central Baghdad, the leader of the Iraqi Accordance Front, Adnan Al-Duleymi, said.

A suicide car bomb aimed at U.S. and Iraqi vehicles in the capital's southern Dora district killed three Iraqis who were shopping in a market and wounded 19 people, police 1st Lt. Maitham Abdul-Razaq said. He said another car bomb killed two soldiers and a civilian downtown.

Police also reported three policemen slain by a car bomb, the shooting deaths of two civilians in separate incidents, and three civilians killed by two roadside bombs.

Gunmen also killed three civilians and wounded eight in a drive-by shooting in central Baghdad, Lt. Bilal Ali Mejeed of the Risafa police station said.

In the volatile western city of Ramadi, meanwhile, a suicide bomber on a motorcycle killed three Iraqi policemen outside a hospital and a car bomb killed four officers at a checkpoint, a police official said, speaking on condition of anonymity because he was not authorized to speak to the media.