BAGHDAD, Jan 10: Gunmen assassinated Baghdad's deputy police chief and a powerful roadside bomb killed two US soldiers when it blew up their armoured vehicle on Monday as insurgents pressed their campaign to wreck Iraq's election.

The explosion in south western Baghdad destroyed a Bradley Fighting Vehicle, one of the army's most advanced pieces of Armour. Interim Prime Minister Iyad Allawi again insisted the vote, Iraq's first national ballot since a US-led invasion toppled dictator Saddam Hussein, would go ahead as scheduled on Jan. 30 despite spiralling violence. But the latest attacks raised fresh doubts over whether Iraq's fledgling security services can protect voters at the polls, even with the backing of US-led forces.

Seeking to shore up security for the election, Britain said it would send a further 400 troops to Iraq. Defence Secretary Geoff Hoon told parliament Britain would soon deploy a battalion of the Royal Highland Fusiliers "for a limited period of time".

The shooting of Brigadier Amer Nayef, the second-ranking police commander in the capital, came just six days after guerillas assassinated Baghdad's provincial governor.

The Al Qaeda-linked group headed by Jordanian militant Abu Musab al-Zarqawi said it had killed Nayef. It has also claimed responsibility for the assassination of the Baghdad governor. The group is behind many of the deadliest suicide attacks in Iraq and the killing of several foreign hostages.

Gunmen killed Nayef and his son, also a policeman, as they left their home in the southern Dora area of the capital, police said. Reuters television pictures showed their bullet-riddled bodies lying on stretchers in a Baghdad hospital morgue. Hours later, a roadside bomb hit the Bradley as it drove through the capital, killing two soldiers and wounding four, the U.S. military said.

The attack followed military assessments that insurgents had gained the ability to plant ever-larger, more powerful bombs to hit American armour on Iraq's perilous highways. Seven US troops were killed last week when their Bradley was destroyed by a roadside bomb in Baghdad.

SUICIDE CAR BOMBING: In another deadly attack in broad daylight on Monday, a suicide bomber in an explosives-packed vehicle resembling those used by police rammed into a police compound in southern Baghdad, killing at least three people, officials said.

Police officers were among the dead and wounded from the explosion, which sent up a column of black smoke over the area. The Army of Ansar al-Sunna group claimed responsibility for the attack, saying it had targeted "apostate forces who are the right-hand men of crusader forces in Iraq."

With three weeks to go before the election, insurgents have stepped up efforts to cripple the US-backed interim government and scare away voters. Iraqi leaders say Sunni-led guerillas also want to provoke sectarian civil war.

A senior US commander said last week that four of Iraq's 18 provinces, including parts of the capital, were still too insecure to hold elections and predicted a surge of violence.

Insurgents have killed more than 100 Iraqis in the past week alone, mostly security force members they regard as collaborators with foreign occupiers. Bloodshed has been especially heavy in the heartland of Saddam's once-privileged Sunni minority.

Many Sunni leaders have called for a delay in the vote, saying persistent violence in Sunni areas would keep voters at home and skew the results in favour of the long-marginalised Shias, who form 60 per cent of Iraq's population.

Allawi, a secular Shia, has rejected any postponement of the election, which is expected to cement the new political dominance enjoyed by Shias since Saddam was toppled in 2003.

A group of leading Sunni clerics meeting a senior American official offered to call off an election boycott in return for a US timetable for a withdrawal from Iraq. -Reuters