If left unchecked, the Taliban insurgency will mean an even larger safe haven from which Al Qaeda would plot to kill more Americans.

'So this is not only a war worth fighting. This is fundamental to the defence of our people.'

During his election campaign, Obama had promised to assess the Afghan strategy and increase troop deployments. He had also promised to end the US mission in Iraq within 16 months of coming to power.

Obama told the war veterans that the Iraq mission will definitely end in 2011. 'And for America, the Iraq war will end,' he said.