Iraq's parliament speaker narrowly escaped an attack in his hometown on Monday, while 21 militants died when a car bomb they were readying mistakenly went off, officials said.

The unrest comes amid the worst protracted period of bloodshed in nearly six years, with more than 1,000 people killed last month as security forces grapple with near-daily attacks and battles with anti-government fighters in Anbar province.

Foreign leaders have pressed the Shiite-led government to reach out to the disaffected Sunni minority to undermine support for militants, but Prime Minister Nuri al-Maliki has taken a hard line ahead of April elections.

On Monday, a convoy carrying parliament speaker Osama al-Nujaifi, Iraq's most senior Sunni Arab politician, was hit by a roadside bomb in the main northern city of Mosul, his office said.

One of Nujaifi's bodyguards was wounded, a police captain and a medical source said, but the speaker himself escaped unharmed.

Mosul and the surrounding Nineveh province, where Nujaifi's brother Atheel is governor, is one of Iraq's most violent areas, with attacks regularly targeting security forces, government officials and civilians.

Also north of Baghdad, a car bomb mistakenly went off in a militant compound, killing 21 insurgents including a suicide bomber, an anti-Qaeda militia leader and a police officer said.

The group were filming a propaganda video of the would-be suicide attacker when a technical glitch set off the car bomb in the Jilam area south of Samarra, according to Majeed Ali, the head of the Sahwa militia force in the city, and a police officer.

Jilam, a mostly rural farming area just south of the mostly-Sunni city of Samarra, has long been an insurgent stronghold.

The blast went off within a compound in the area, Ali and the police officer said.

Government deadline to militants

Elsewhere on Monday, attacks in Baghdad and the nearby towns of Mussayib and Balad left five people dead, while three militants were also killed in clashes with security forces.

More than 1,000 people were killed nationwide last month, according to government data, the highest such figure since 2008, with violence surging markedly higher in recent months.

No group has claimed responsibility for most of the bloodshed, but Sunni militants including the Islamic State of Iraq and the Levant, a powerful jihadist group, are often blamed.

Analysts say that while the vast majority of Sunni Arabs do not support militancy, frustration with the Shiite-led authorities means they are less likely to cooperate with security forces in providing intelligence against insurgents.

The violence comes amid a standoff in Anbar province, a mostly Sunni desert region bordering Syria, where militants have held parts of one city and all of another for weeks.

Anbar's governor over the weekend gave militants controlling Fallujah one week to surrender, as government forces made steady progress in nearby Ramadi as part of efforts to end the crisis.

Government forces have largely stayed out of Fallujah, fearing that an incursion could spark a drawn-out urban conflict with high numbers of casualties.

The city was a bastion of the Sunni insurgency following the 2003 US-led invasion, and American troops there fought some of their costliest battles since the Vietnam War.

The Anbar stand-off has prompted more than 140,000 people to flee their homes, the UN refugee agency said last month, calling it the worst displacement in Iraq since the peak of sectarian fighting between 2006 and 2008.