The US military will reportedly target the Taliban and al-Qaeda in a spring offensive in Afghanistan.
The Chicago Tribuneis reporting that thousands of troops will be involved and that refugees in Pakistan used by fugitive Osama bin Laden's al-Qaeda network will also be attacked.
The Pakistani government has said it will not allow such an operation to extend into its territory.
Pakistani President Gen Pervez Musharraf has allowed only a very limited US military presence in his country. He has co-operated with Washington against al-Qaeda but is under pressure from Islamic parties at home.
The Pentagon and the US military's Central Command have refused to comment.
But a US official said the offensive would be similar to previous operations in which troops supported by warplanes went after guerrillas and transit routes in the Afghan mountains near Pakistan.
US forces invaded Afghanistan a month after the September 11th but have failed to capture Osama bin Laden - the man they hold respnsible for the attacks.