According to reports, as many as 25,000 Afghan soldiers are said to have gathered at their border with Pakistan.
Skud missiles are also said to have been deployed on the border.
It follows the news that Afghanistan has closed its air space and has threatened to shoot down any foreign aircrafts.
Earlier talks between a Pakistan Government delegation and the Taliban regime collapsed after the Taliban had been urged to give up America's prime suspect for last Tuesday's terrorist attack, Osama bin Laden.
Residents in Afghanistan are said to be fleeing the main cities fearing US retaliation with many civilians attempting to cross the border to Pakistan.