US:While Britain insists that the decision to withdraw its troops from Basra Palace was taken in full consultation with American military commanders, there is no disguising the disappointment and anxiety developments in southern Iraq have aroused in Washington.
Home to two-thirds of Iraq's oil resources, with the country's only maritime access, stability in Basra is crucial to any hope of creating a sustainable economy in Iraq.
The White House has avoided openly criticising Britain, but senior military figures and commentators close to the administration have been complaining for weeks that the British government is preparing for a full withdrawal from Iraq.
Retired general Jack Keane, an architect of the US military "surge" in Iraq, said that US commanders were frustrated by a "general disengagement" by British forces in Basra, which he said was allowing security to deteriorate there.
"I think it has been gradually deteriorating, with almost gangland warfare and the lack of ability of the police to control that level of violence - so the situation is gradually getting worse," he told the BBC.
Gen Keane said that US commanders wanted to avoid having to fill a security vacuum if Britain withdrew its remaining troops from Basra airport.
"That situation could arise if the situation gets worse in Basra if and when British troops leave," he said.
British foreign secretary David Milliband and defence secretary Des Browne sought to quell US criticism in an opinion piece published in a number of American newspapers. Their prediction that "Basra province will in months, not years, be judged to have met the conditions for transfer to full Iraqi security control" may, however, have further fuelled US fears of a hasty British withdrawal.
The International Crisis Group reported this summer that Basra is plagued by "the systematic misuse of official institutions, political assassinations, tribal vendettas, neighbourhood vigilantism and enforcement of social mores, together with the rise of criminal mafias that increasingly intermingle with political actors".
Britain's withdrawal follows the failure of a strategy last year to clear districts of violent militias similar to that now employed by US forces in Baghdad, a fact that has not escaped Democrats and some Republicans who are calling for the start of a withdrawal of US forces.