US has sent additional heavy tanks and armoured vehicles to Iraq to
combat the recent upsurge in attacks on its forces there.
Thousands of civilians have been displaced by
the fighting in Falluja
The move is at the request of military commanders on the ground.
BBC Pentagon correspondent Nick Childs says it marks a sharp
reversal of strategy, and highlights their concern about the
escalating violence in Iraq.
The deployment comes as US forces continue to attack insurgent
targets in the restive city of Falluja.
The predominantly Sunni Muslim city, 50km (30 miles) west of
Baghdad, has spearheaded opposition to the US-led occupation of
United Nations Secretary General Kofi Annan has warned that
American military action in Falluja could be fuelling the resistance
to the US-led occupation of Iraq.
But US President George W Bush said the military would take
whatever action was necessary to secure the city.
The reinforcements being sent to Iraq include 28 of the giant M1
The deployment reflects the inadequacy of the standard military
personnel transporter in Iraq, the Humvee, to deal with roadside
bombs and rocket-propelled grenades.
April has seen more than 120 US troops killed in Iraq - by far
the highest casualty rate since the toppling of Saddam Hussein a
Our correspondent says that many of the US units now in Iraq have
deployed only in recent months.
They were sent without much of their heavy equipment because at
the time it was thought that lighter, more mobile forces were what
was needed as the security situation appeared to be improving.
With the upsurge in fighting, he adds, US marine and army
commanders urgently requested more firepower and protection for
"That armour is either in Iraq now or is arriving as we speak. So
those requests were quickly filled," US Marine Corps Major General
John Sattler told reporters.
Recent days have seen US air strikes against insurgents in
Falluja, which has been encircled by a force of US marines.
Jet aircraft, helicopters and AC-130 gunships have bombed and
strafed targets in several districts of the city.
Marine commanders maintain that they have called in air support
only after coming under enemy fire.
They say a ceasefire agreed earlier this month is still valid,
but that they will respond with overwhelming force when fired upon.
Captain Christopher Logan, a spokesman at the US Marines base
just outside Falluja, said: "We ceased fire and they kept firing. If
they are stupid enough to attack us, we'll destroy them."
The US military says it is holding back from an all-out assault
on the city of 300,000 people, in the hope that the insurgents might
yet agree to turn in their heavy weapons.
Talks between US forces and local leaders to secure a solution
continue alongside the fighting.
Gen Sattler said there were "somewhere around 1,500" guerrillas
in Falluja, including former members of Saddam Hussein's Republican
Guard military units and foreign Islamic militants.
Speaking in Washington, President Bush said: "Our military
commanders will take whatever actions necessary to secure the city."
He added that there were "pockets of resistance" in the city but
"most of Falluja is returning to normal".
Secretary General Annan, whose organisation is helping form an
interim Iraqi government in line with US plans to transfer power on
30 June, urged US forces to show restraint.
"The more the occupation is seen as taking steps that harm the
civilians and the population, the greater the ranks of the
resistance grows," he told a news conference in New York.
Doctors in Falluja say some 600 people have been killed since the
siege began three weeks ago.
Thousands have fled the city, but many are now attempting to
return, despite the fighting.
An unconfirmed report says US marines manning a checkpoint opened
fire on a minibus on Thursday morning, killing four civilians.
The US military operation in Falluja began on 5 April following
the gruesome killings of four American civilian contractors there.
Elsewhere in Iraq, two US soldiers have been killed in separate
attacks by guerrillas.
The US military said one died in a rocket-propelled grenade
attack in eastern Baghdad, while the other was killed when a
roadside bomb exploded near a convoy close to the town of Baquba,
40km (24 miles) north of the capital.
Thursday also saw a foreign civilian, possibly a South African,
killed in a drive-by shooting in the southern city of Basra.
In the US, a new opinion poll suggests dwindling support among
Americans for the invasion and occupation of Iraq.
Just 47% of 1,042 Americans questioned believed invading Iraq was
the right thing to do, the lowest support recorded in the polls
since the war began.