BAGHDAD >> Thousands marched on government buildings and clashed with security forces today in cities across Iraq in an outpouring of anger that left 11 people dead — the largest and most violent anti-government protests in the country since political unrest began spreading in the Arab world weeks ago.

In northern Iraqi cities, security forces trying to push back crowds opened fire, killing nine demonstrators, In the western Anbar province two people were shot and killed in a protest. In the capital of Baghdad, demonstrators knocked down blast walls, threw rocks and scuffled with club-wielding troops who chased them down the street.

The protests, billed as a “Day of Rage, were fueled by anger over corruption, chronic unemployment and shoddy public services from the Shiite-dominated government. Shiite religious leaders discouraged people from taking part, greatly diminishing the Shiite participation and the overall size of the crowd in a country where such religious edicts hold great sway.

In the Sunni enclave of Azamiyah, one of the residents said that people there did not want to attend because they feared being labeled Saddamists. “The government has already convicted anyone who takes part in the demonstrations by accusing them of terrorism,” said 41-year-old Ammar al-Azami.

A Shiite resident from the New Baghdad neighborhood of the capital, Khalil Ibrahim, 44, one of about 3,000 protesters in downtown Baghdad, railed against a government that locks itself in the highly fortified Green Zone, home to the parliament and the U.S. Embassy, and is viewed by most of its citizens as more interested in personal gain than public service.

“We want a good life like human beings, not like animals,” Ibrahim said.

A report released last month by the U.S. reconstruction watchdog agency noted that Iraqi officials are trying to improve the nation’s electricity grid with hopes of meeting power demands by 2014.

“The lack of perceived improvements in Iraq’s water, sewage, and electricity systems could lead to popular unrest more so than political or sectarian disagreements,” the special inspector general for Iraqi reconstruction concluded.

The center of Baghdad was virtually locked down today, with soldiers searching protesters entering Liberation Square and closing off the plaza and side streets with razor wire. The heavy security presence reflected the official concerns that demonstrations here could gain traction as they did in Egypt and Tunisia, then spiral out of control.

Iraqi army helicopters buzzed overhead, while Humvees and trucks took up posts throughout the square, where flag-waving demonstrators shouted “No to unemployment,” and “No to the liar al-Maliki,” referring to Iraqi Prime Minister Nouri al-Maliki.

Demonstrators trying to get across a bridge going from the square to the Green Zone clashed with security forces. The demonstrators knocked down some of the concrete blast walls that were put up Thursday night and threw rocks at troops who beat them back with batons. Six riot police and 12 demonstrators were wounded in the melee, according to police and hospital officials.

The protests stretched from the northern city of Mosul to the southern city of Basra, reflecting the widespread anger many Iraqis feel at the government’s seeming inability to improve their lives.

The most deadly clashes came in the Mosul, 225 miles northwest of Baghdad. Hundreds of protesters gathered in front of the provincial council building, demanding jobs and better services, when guards opened fire, according to a police official. A police and hospital official said five protesters were killed and 15 people wounded.

Black smoke could later be seen billowing from the building.

A crowd of angry marchers in the northern city of Hawija, 150 miles north of Baghdad, tried to break into the city’s municipal building, said the head of the local city council, Ali Hussein Salih.

Security forces trying to block the crowd opened fire, killing three demonstrators and wounding 15, local officials said. Protesters set fire to three police stations and the municipal council building, said Brig. Gen. Sarhad Qadir. The Iraqi Army was eventually called in to restore order.

Around 1,000 demonstrators clashed with police in the western city of Fallujah 40 miles west of Baghdad, witnesses said. At least two people were killed and 14 others injured in riots in Anbar province, said Sheik Efan Saadoun, a provincial councilor in Anbar province; he did not know whether the deaths came in Fallujah or Ramadi where protesters also clashed with authorities.

Police used stun grenades to ward off about 1,000 demonstrators in Saddam Hussein’s former hometown of Tikrit and in the northern city of Kirkuk hundreds of people rallied against corruption in front of the provincial headquarters.

In the south, about 4,000 people demonstrated in front of the office of Gov. Sheltagh Aboud al-Mayahi in the port of Basra, Iraq’s second-largest city, 340 miles southeast of Baghdad. They knocked over one of the concrete barriers and demanded his resignation, saying he’d done nothing to improve services.

They appeared to get their wish when the commander of Basra military operations, Maj. Gen. Mohammad Jawad Hawaidi, told the crowd that the governor had resigned.

And in the southern city of Karbala, about 1,000 protesters rallied for better services.

In recent weeks, there had been scattered anti-government protests in Iraq. While most have been peaceful, a few have turned violent and seven people have been killed. The biggest rallies have been in the northern Kurdish city of Sulaimaniyah, 160 miles northeast of Baghdad, against the government of the self-ruled region.

Police opened fire today in the town of Kalar, south of Sulaimaniyah, when a crowd of demonstrators closed in on the headquarters of one of the main ruling parties, police and hospital officials said. One demonstrator was killed and 25 others wounded.

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

On the eve of the marches, al-Maliki urged people to skip the rally, which he alleged was organized by Saddamists and al-Qaida — two of his favorite targets of blame for an array of Iraq’s ills. He offered no evidence to support his claim.