BAGHDAD, Iraq — Insurgents unleashed a series of deadly bombings in Iraq's capital and beyond yesterday, staging a series of coordinated and increasingly sophisticated assaults that killed at least 65 over two days and appeared timed to deflate hopes in Washington and Baghdad that the nation's first democratically elected government would curb spiking violence.

At least 17 Iraqis and one U.S. soldier were killed yesterday. The military also announced that six other U.S. soldiers had been killed and six wounded in Iraq since Thursday.

The attacks continued for a third straight day today when insurgents armed with machine guns and rocket-propelled grenades ambushed a police checkpoint in Baghdad, killing five policemen and wounding one.

A pickup truck stopped near the checkpoint and insurgents jumped out and fired machine guns. They were joined by other militants who had been hiding behind nearby trees, said police Lt. Col. Sabah Hamid al-Firtosi.

The U.S. Army, meanwhile, released a report clearing American soldiers in the death of an Italian intelligence agent in Iraq and recommending no disciplinary action. The agent was escorting a released Italian hostage when American soldiers fired on their car.

The Italian Foreign Ministry had no comment on the American report. But on Friday, Foreign Minister Gianfranco Fini said Italy did not agree with the U.S. version of events.

Italy was expected to release its own report on the shooting within days.

At least five car bombs rocked Baghdad yesterday, U.S. military spokesman Greg Kaufman said. Six more exploded in the northern city of Mosul, which also has seen frequent attacks. There was also a bombing in Baqouba and in Fallujah.

U.S. and Iraqi officials had hoped to curb support for the militants by including members of the Sunni Arab minority in a new Shiite-dominated Cabinet that will be sworn in Tuesday. Sunnis, who held monopoly power during the rule of Saddam Hussein, are believed to be the backbone of Iraq's insurgency. Most stayed away from landmark Jan. 30 parliamentary elections — either in protest or out of fear of attack.

However, the lineup named by incoming Prime Minister Ibrahim al-Jaafari after months of political wrangling excluded Sunnis from meaningful positions and left the key defense and oil ministries — among other unfilled posts — in temporary hands.

Approval of the Cabinet Thursday was met with an onslaught of bombings — including several coordinated suicide attacks — in the capital and elsewhere.

Fearing the violence could spread, Iraq's neighbors pledged at a meeting yesterday in Turkey to boost border security and increase intelligence sharing with the country's newly elected government, steps that could stem the flow of insurgents slipping across the poorly patrolled frontiers. Syria, meanwhile, announced it would restore relations with Iraq after more than two decades.

The U.S. investigation into the March 4 checkpoint killing of Nicola Calipari said the incident might have been prevented by better coordination between the Italian government and U.S. forces in Iraq.

Calipari was mistakenly shot soon after he had secured the release of Italian journalist Giuliana Sgrena from Iraqi militants, who had held her hostage for a month. U.S. soldiers fired on the Italians' vehicle as it approached an American checkpoint near Baghdad's airport. Sgrena and another Italian agent were wounded.

The U.S. investigation concluded the vehicle failed to slow down as it approached the checkpoint, and the soldiers who fired at it acted according to the rules of engagement.

The Americans maintain the soldiers fired warning shots in the air, then shot at the engine block because the car was speeding. But the survivors insist they saw the beam of a warning light virtually at the same time gunfire broke out. The surviving intelligence agent also testified he was driving slowly.

The American deaths announced yesterday included one killed yesterday in gunfire in Khaldiyah, 75 miles west of Baghdad, two killed Friday in a roadside bombing west of Baghdad and four killed and two injured in another bombing Thursday in Tal Afar, near the Syrian border.

Four more U.S. soldiers were wounded when their Humvee rolled into a ditch Friday night near Abu Ghraib prison, west of Baghdad, the U.S. military said.