NATO Chief Anders Fogh Rasmussen has expressed serious concern over the deepening split between the US and its Western allies on the handling of war in Afghanistan.

"I'm a little concerned about the doubts I hear these days in the United States about NATO," Rasmussen said in his first speech in the US as secretary-general.

The speech comes after US General McChrystal warned that the NATO mission would 'likely result in failure' unless more troops are deployed across the war-ravaged country.

Canada and several European countries seem to oppose further commitments for the mission in Afghanistan, where insurgency has skyrocketed over the past months.

NATO chief noted he was aware of frustrations among US officials caused by 'the restrictions some NATO nations put on their forces'.

US President Barack Obama has said there is 'an almost reflexive anti-Americanism', which is stopping some countries from stepping up to the plate, according to US media outlets.

But Rasmussen highlighted Canada and Europe's role in the eight-year-long Afghan war.

"Talking down the European and Canadian contributions - as some here in the US do, on occasion - can become a self-fulfilling prophecy," the BBC quoted Rasmussen as saying.

The US-led forces lost 77 troops in August, setting a new monthly record since the occupation began in 2001.

Foreign troop casualties in Afghanistan are at record levels, with at least 365 deaths reported in 2009.

"I will not accept from anyone the argument that Europeans and Canadians are not paying the price for success in Afghanistan," Rasmussen emphasized.

"While body count is no measure of solidarity, it is, unfortunately, a symbol of commitment. Over 20 countries have had their soldiers killed, some in large numbers."

The mounting number of Western soldiers coming home in body bags has sent support for the war plummeting in Europe, Canada and the United States.

Despite the presence of over 100,000 troops in the war-torn country, Afghanistan is witnessing the highest level of violence since the 2001 invasion.

The insurgency has intensified in the eastern and southern provinces, as pressure is mounting on the US and its western allies to pull troops out of the country amid continuing troop causalities.

JR/AKM