BAGHDAD  A series of car bombings devastated government institutions across Baghdad on Tuesday, provoking public and political denunciations of the country’s prime minister and the security forces he oversees. The attacks came as officials agreed at last to set a date in March for a national election.

The bombings, a coordinated assault on the capital, highlighted an ominous convergence of politics and violence, which American and Iraqi officials have long warned will mar the country’s election. The vote, originally scheduled for January, was delayed by ethnic and sectarian disputes resolved only two days ago.

Five bombs, at least three detonated by suicide attackers, struck a courthouse, two colleges, a mosque and a bank. They created chaos across the city, locking down entire neighborhoods, overwhelming the police and rescue workers, and filling hospitals with the wounded. In one, a woman with her hair scorched and neck bloodied agonized as her child lay dying in a hallway.

At least 121 people were killed and more than 400 were wounded, according to police and hospital officials.

The attacks appeared intended to cripple the government’s basic ability to function, and at least in part they succeeded. Two government institutions struck on Tuesday, the Finance Ministry and an appeals court, had only just relocated to new buildings after similar attacks destroyed their old offices in August and October.

Many victims, standing amid debris and carnage, blamed Iraq’s army and police force, which have taken charge of security as American forces have withdrawn from cities. They also linked the attacks to the protracted political jockeying over the election. “Are we cursed?” yelled a young woman near the mosque that was struck in Qahira, in northeast Baghdad. She had burns over her arms and legs. “When will we be finished with this election issue?” Prospective candidates blamed the security forces and the government for once again failing to protect the heart of Baghdad.

The attacks were the worst in Iraq since twin suicide bombings destroyed three government agencies on Oct. 25, killing at least 155. They fit a pattern of spectacularly lethal attacks in the capital, followed by weeks of relative calm. In August, two suicide car bombs struck the country’s Finance and Foreign Ministries, killing at least 122. Those attacks became known as Bloody Sunday and Bloody Wednesday, respectively. Officials and average Iraqis promptly added the adjective to Tuesday, as well.

Image Rescuers carried a victim of a bomb attack in Baghdad on Tuesday. Five bombs were set off in the capital, at least three of them by suicide bombers. Credit... Bassim Shati/Reuters

“We can only hope that not every day will turn into Bloody Days,” Wathab Shakir, a Sunni lawmaker, declared during a stormy session of Parliament convened hours after the attacks.

The bombings underscored the inability of Iraq’s security forces to stop carefully orchestrated attacks, despite an overwhelming presence at checkpoints that punctuate every major street in Baghdad.

Not one of dozens of lawmakers who fulminated in Parliament expressed any confidence in Iraq’s security, a rare display of unity across political and sectarian divisions.

The session included calls for the resignations of senior military and police commanders, particularly the head of the Baghdad Operations Command, Gen. Aboud Qanbar, appointed by Prime Minister Nuri Kamal al-Maliki. “The Iraqi government holds a great deal of responsibility for the bombings today and those in the past because of its negligence,” said Hassan al-Shimary, a member of Parliament from Fadhila, a party that joined a Shiite-led coalition challenging Mr. Maliki in the coming election.

The blasts began shortly after 10 a.m. and reverberated through the city for the next 50 minutes, sending enormous plumes of black smoke skyward. The first occurred in Dora, in southern Baghdad, when a suicide bomber detonated his car as he passed a police patrol near the entrance to a vocational college.

At least nine people were killed there, including three police officers. At least 31 others were hospitalized, many of them students. Broken glass, body parts, blood and sewage covered the street.

One of the deadliest attacks struck the headquarters of the Rafaidyan Bank downtown, where many workers from the Finance Ministry had moved after the ministry’s building was destroyed in the August bombings. Dozens died there, though officials did not have an exact toll.

“The bomber wanted numbers,” Capt. Saif al-Dairi of the Federal Police said at the scene in Dora. “He wanted to kill as many people as possible.”