In marathon meetings over five days with allied defence ministers and other security leaders and a quick sidetrip to Pakistan, Gates used tough talk wrapped in a congenial package to press his agenda.

His trip ended Monday.

Speaking during the journey to an audience that included many sceptics of the war in Iraq, Gates was blunt: "If the United States and our partners in Iraq fail, and there is chaos in Iraq, every member of this alliance will feel the consequences."

During more than 15 private meetings with his Nato colleagues, he pressed for more economic and reconstruction support in Afghanistan. Failure to step up and take the offensive against the Taliban as spring comes, he warned them, would be shameful.

Gates also used humour and humility throughout the five-day, three-country diplomatic swing that was clearly aimed at mending fences.

He grabbed headlines when he dismissed a scorching speech by Russian President Vladimir Putin assaulting US foreign policy. Characterising it as a throwback to the Cold War, he said the countries must move on and work as partners, adding, "One Cold War was quite enough."

Meanwhile, Nato and Afghan forces killed 22 Taliban fighters in separate clashes in a southern Afghan province where hundreds of militants have gathered, a police official said yesterday.

More than 300 British marines cleared "a stronghold of Taliban extremists" around a hydroelectric dam in the Kajaki district of Helmand province a region that has been the target of Taliban attacks, Nato's International Security Assistance Force said.