Robert Gates, the US Defence Secretary, risked an unprecedented rift with Britain and other close allies after accusing Nato countries fighting in southern Afghanistan of lacking experience in counter-insurgency warfare.

Mr Gates said failings in the south were contributing to the rising violence in the fight against the Taleban.

His outspoken criticism, voiced in an interview with an American newspaper, provoked instant reactions from Britain, Canada and the Netherlands, the three most prominent members of the alliance, who have endured much of the fiercest fighting in southern Afghanistan.

The Dutch were so angry at what appeared to be direct criticism that they summoned the US Ambassador in The Hague to explain Mr Gates’s comments. British and Dutch officials refused to believe that the criticism was directed at them, but Eric Adelman, the US Assistant Secretary of Defence, nonetheless had to ring around Nato capitals to give reassurance that Mr Gates was not attacking any individual member.

Mr Gates was quoted as saying: “I’m worried we’re deploying [military advisers] that are not properly trained, and I’m worried we have some military forces that don’t know how to do counter-insurgency operations.”

As officials tried to smooth over the apparent rift, his comments drew a fierce response. Patrick Mercer, a Conservative MP and a former British Army officer, said they were “bloody outrageous”. He said: “I would beg the Americans to understand that we are their closest allies, and our men are bleeding and dying in large numbers.”

Britain has 7,800 troops in southern Afghanistan, where 81 have been killed. The Dutch and the Canadians have also lost a substantial number of soldiers in counter-insurgency operations against the Taleban.

One British official said: “The Pentagon was very swiftly on the phone to put Mr Gates’s words in context. He wasn’t having a go at us. There was no need to summon the US Ambassador because we were reassured that Mr Gates was referring to the history of Nato, not to the individual efforts of Nato members in southern Afghanistan.”

Canadian Foreign Ministry sources said that officials had been in touch with the Pentagon after Mr Gates’s comments had appeared in the newspaper. Last year Canada, which has 2,500 troops in Kandahar province in the south, was involved in one of the fiercest confrontations with Taleban forces in the Panjwayi district. Backed by American and other Nato forces, the Canadians defeated the Taleban and drove them out of the area.

Geoff Morrell, the Pentagon press secretary, told The Times that Mr Gates “was not criticising any specific country. But he did want to make it clear that he believes Nato as an alliance has not redirected its training quickly or effectively to deal with asymmetric threats. Mr Gates has always praised British troops for their professionalism, courage and sacrifices.”

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