The first of four major blasts targeted the headquarters of Allawi's al-Wifaq Party (Iraqi National Accord) in al-Zaitun street in Baghdad on Monday.
Iraqi journalist Ziyad al-Samarrai told Aljazeera that the headquarters had previously come under repeated mortar attacks, but this time a bomber managed to break through the checkpoints of the headquarters and blow up his booby-trapped car.
Seven Iraqi policemen were killed, including an officer, and 23 others injured in the explosion at a checkpoint near al-Wifaq Party headquarters, police sources told al-Samarrai.
The journalist reported that ambulances rushed to the explosion site and US forces and Iraqi police cordoned off the area while helicopters hovered above.
Late on Monday, a British Foreign Office spokeswoman in London said three British nationals were killed in an explosion in Baghdad.
She could not confirm that they had died in the blast targeting Allawi's party office.
Other Baghdad attacks
Al-Samarrai also reported that the Iraqi National Guard headquarters in al-Ghazaliya area, west of Baghdad, came under heavy mortar attacks. "The attacks lasted for more than 20 minutes," he said.
"Violent clashes have also erupted in al-Adhamiya area and al-Shaab city," he added.
Scores of Iraqi police have been
wounded and 38 killed in 24 hours
Separately, a US military armoured vehicle was damaged when an explosive device detonated in al-Mutasim neighbourhood in central Samarra city, sources told Aljazeera.
Violent clashes later erupted between US forces and fighters, using rocket-propelled grenades and machine guns. Captain Mitch Zorn also confirmed that the Green Zone had come under multiple attacks.
Outside the capital
Another six members of the Iraqi National Guard were killed and four more wounded in two separate explosions in Tikrit, according to security forces.
And another car bomb also exploded near a US military base near Balad, a town north of Baghdad. Six Iraqi national guardsmen died and another eight were wounded.
The attack occurred in the same place where 25 national guardsmen died on Sunday and means that at least 38 members of Iraq's fledgling security forces have died in the past 24 hours.