More British troops are being sent to Iraq over the weekend, defence secretary Geoff Hoon has revealed.
As many as 10,000 British troops are already in Iraq
The Ministry of Defence has been reviewing troop numbers following recent attacks, and Mr Hoon said he would reveal details of any extra deployment early next week.
But he said a company of around 150 from the 2nd Battalion Light Infantry will travel from Cyprus to Baghdad over the weekend.
The battalion has been designated as a theatre reserve force for Iraq since August.
Mr Hoon revealed the move in a letter to Conservative and Liberal Democrat shadow defence secretaries. Bernard Jenkin and Paul Keetch, and the Commons Defence Select Committee Chairman, Bruce George.
A spokeswoman at the MoD confirmed that 120-150 troops would be deployed and that this had been on the cards for the past month.
Paul Keetch welcomed the development but said that "more troops alone will not solve the problems of the Coalition in Iraq."
He said only the UN could "restore Iraq's sovereignty and command legitimacy."
Earlier, the deputy commander of coalition forces in Iraq, General Freddy Viggers, told the BBC the number of Iraqi police and security personnel was the important issue.
The US Defence Secretary, Donald Rumsfeld, said 10,000 more international troops are needed to tackle the security situation in Iraq.
But a US draft resolution seeking greater international help has been opposed by France and Germany.
The review of British troops is being carried out by commanders on the ground in Iraq.
An MoD spokesman told BBC News Online: "It's being done as quickly as possible. When Parliament comes back (on 8 September) we would give them a statement."
Foreign Secretary Jack Straw has reportedly warned the prime minister another 5,000 troops should be sent to Iraq.
Speaking at his monthly televised news conference on Thursday, Mr Blair said people should not make too much of the move because the issue was constantly examined.
"There are no decisions which have been taken on additional troops," he said.
He said it was a "serious situation" in Iraq caused by a small band of extremists, not ordinary Iraqis.
General Viggers told BBC2's Newsnight programme the coalition wanted to double the numbers of Iraqi police, the civil defence core and soldiers controlling the borders over the next two months.
"It's not about numbers, it's about the right sorts of troops, to get
involved with the Iraqis, to get them doing more for themselves in the security
environment," he said.
Defence analyst Paul Beaver told BBC News two types of British troops were needed - those to maintain order and specialist soldiers such as engineers to help rebuild the infrastructure.
Eleven British troops and more than 60 American soldiers have been killed in action since President George Bush declared an end to major combat operations on 1 May.
Corporal Dewi Pritchard, from Wales, who was killed in an ambush in southern Iraq last month, is to be buried in his home town of Bridgend on Friday.
The deadline for British police officers applying to work in Iraq to help maintain order is also on Friday.
Mr Rumsfeld arrived on a surprise visit to military commanders in Baghdad and said "maybe another division" was required to help American and British forces.
The US has put a draft resolution on Iraq before the United Nations Security Council in New York.
But there was a blow to US hopes of getting a bigger role for the UN as Germany and France said the current US plans did not go far enough.
They said it does not give the UN a big enough role in Iraq's reconstruction.
The White House has said any military force in Iraq would have to be under the control of an American commander.