Baghdad: A rapid series of attacks spread over a wide swath of Iraqi territory killed at least 50 people on Thursday, targeting mostly security forces in what appeared to be another strike by al-Qaida militants bent on destabilising the country.

The apparently coordinated bombings and shootings unfolded over two-and-a-half hours in the capital Baghdad, where most of the deaths were, and 11 other cities.

They struck government offices, restaurants and one in the town of Musayyib hit close to a primary school. More than 200 people were injured.

"What is happening today are not simple security violations, it is a huge security failure and disaster," said Ahmed al-Tamimi, who was working at an Education Ministry office a block away from a restaurant that was bombed in the Shiite neighbourhood of Kazimiyah in northern Baghdad.

He described a hellish scene of human flesh and pools of blood at the scene.

"We want to know: What were the thousands of policemen and soldiers in Baghdad doing today while the terrorists were roaming the city and spreading violence?" al-Tamimi said.

There have been a series of large-scale attacks by insurgents since the last US troops left Iraq in mid-December at the end of a nearly 10-year war.

Shortly after the withdrawal, a major political crisis with sectarian undertones erupted as well when Shiite-dominated authorities sought to arrest Sunni Vice President Tariq al-Hashemi on allegations he commandeered death squads targeting security forces and government officials.

While no group immediately claimed responsibility for the latest attacks, targeting security officials is a hallmark of Al-Qaida in Iraq.