The envoy said that problems facing displaced people were 'overwhelming'
US envoy Richard Holbrooke has said that the public mood in Pakistan is swinging against the militants towards the government.
Mr Holbrooke, who recently returned to the US from Pakistan, told reporters about the "growing consensus" of the need to face down insurgents.
But he also said that Pakistan was in the throes of a major refugee crisis.
More than two million people have been displaced because of the army's offensive in Pakistan's Swat valley.
Mr Holbrooke, who toured refugee camps in the north-west of the country, called the situation there a "major, major crisis" and said people should be allowed return home as soon as possible.
He added that the camps should not be allowed to become permanent.
But he insisted that the army's offensive had the support of the Pakistani public.
Mr Holbrooke said that "outrages perpetrated by the Taliban" such as Tuesday's bombing of the Pearl Hotel in Peshawar which killed at least 18 people, were resulting in a dramatic change in attitudes.
Letter to India
The BBC's Adam Brookes in Washington said that US officials and politicians have long expressed the concern that the fight against extremism in the region does not have whole-hearted support of Pakistan's government and people.
However Mr Holbrooke said his conversations with senior Pakistani military officers had assured him of their clear strategy in the battle against the militants.
In recent days the Pakistani army has been targeting militants on a variety of fronts in the north-west of the country. Apart from the ongoing offensive in the Swat valley, the army has been bombarding positions in the semi-tribal areas around North Waziristan.
Separately, Mr Holbrooke said that the US Undersecretary of State William Burns had handed India a letter from President Barack Obama.
"This administration believes that what happens in Afghanistan and Pakistan is of vital interest to our national security, and .. that India is a country that we must keep in closest consultation with," he said.
He declined to divulge the contents of the letter.