Insurgents have infiltrated Iraq's police force, but the extent to which they have done so remains unclear, Iraq's national security advisor Muwaffaq Rubaie said on Tuesday.
"Our Iraqi security forces in general, police in particular, in many parts of Iraq, I have to admit, have been penetrated by some of the insurgents, some of the terrorists as well," he told BBC television. "I can't deny this."
Rubaie's remarks came a day after British troops stormed a police station in the southern city of Basra, looking for two soldiers later found and freed from a house where they had been taken from a police cell by militiamen.
The incident triggered concern about collusion between the Iraqi police and militiamen, as the US and UK -- which invaded Iraq in March 2003 -- wonder how much longer they will need to maintain a military presence.
Rubaie said Iraq's interim government was putting into place "a very scrupulous, very meticulous vetting procedure" as it recruits new members of the police and armed forces.
It should, he said, "clean our security forces as well as stop any penetration in future from the insurgents and terrorists."
He added: "I can't give you a percentage of the extent of the penetration, but I have to admit that the Iraqi security forces are penetrated. To what extent I don't know."
The UK said yesterday that it would not cut and run from Iraq, and sought to calm fury in an increasingly volatile south over the rescue of the two undercover British soldiers.
The British operation followed rioting that began, according to police and local officials, when the two soldiers fired on a police patrol. At least two Iraqis were killed in the violence.
"We do not have designs to stay [in Iraq] as an occupying imperial power. Nor are we going to cut and run because of terrorists," British Defense Secretary John Reid was quoted as saying by the Daily Telegraph newspaper.
Reid, echoing past comments by British Prime Minister Tony Blair who has been US President George W. Bush's main ally on Iraq, said the transformation of the country into a democratic society would not be accomplished without great effort.
"Which is why we have to stay there and go through the dark periods ... there is light at the end of the tunnel," he said.
The UK, which has 8,500 troops in Iraq, said on Sunday it would send more if necessary. But a leaked memo signed by Reid in July envisioned bringing most home over the next year.
The Telegraph said Reid and British defense chiefs were to meet Iraqi Prime Minister Ibrahim Jaafari in London yesterday to discuss security issues.
Haider al-Ebadi, an adviser to Jaafari, told a news conference in Baghdad on Tuesday: "It is a very unfortunate development that the British forces should try to release their forces the way it happened."
But a later statement from Jaafari's office said there was no crisis in relations with Britain and added the interior ministry was investigating the incident in the south, largely populated by Iraq's Shiite Muslim majority.
"In the meantime we urge all sides to remain calm," the statement said.
Meanwhile roadside bombs exploded near three US convoys in and around Baghdad yesterday, wounding two soldiers, an official said. The attacks came one day after the death toll for US forces in the Iraq war rose to more than 1,900 since the invasion.