The forecast by the International Institute of Strategic Studies (IISS) was released yesterday, as the number of US soldiers killed in the country rose to the psychologically significant watermark of 2,000, a toll five times higher than that of the 1991 Gulf War. The total was reached after a roadside bomb killed two marines west of Baghdad.
The US Senate marked the moment with a moment of silence. "We owe them a deep debt of gratitude for their courage, for their valour, for their strength, for their commitment to our country," said Majority Leader Bill Frist.
The critical analysis by the IISS is regarded as significant because the body is independent but also has access to the political and military establishments on both sides of the Atlantic.
In its annual review, The Military Balance, the IISS says the policy of substituting Iraqi forces for US and British ones has so far proved ineffective. It also warns that Washington may have to negotiate an end to the insurgency, which has continued unabated since President George Bush declared that the war had been successfully concluded.
Dr John Chipman, the director of IISS, said: "US plans to shift the burden of fighting the insurgency from their own forces to the newly trained Iraqi army have not to date born dividends.The insurgency, on the other hand, still retains the ability to kill Iraqi and US soldiers. Iraq continues to be a very unstable country."
Patrick Cronin, the IISS's director of studies, said the next US presidency would have to deal with the Iraq situation. "The current administration is not one to announce large-scale troop reductions," he said.
The number of British deaths since the invasion stands at 97. Britain has blamed Iran for supplying technology to Shia militias in Iraq. But the IISS said that, although it was possible for equipment to be smuggled across the Iran/ Iraq border, there "must be some doubt" whether the Iranian government was directly implicated.
* Al-Qa'ida in Iraqclaimed responsibility for the attacks on Monday that killed at least 20 people at a hotel used by journalists in Baghdad, according to a website.