Pakistan is one of the largest recipients of U.S. foreign aid and the cutback announced is only a small proportion of the billions in civil and military assistance it gets each year.

But it could presage even greater cuts. The aid freeze targets funds used to fight Taliban insurgents.

Calls are growing in the United States to penalize Islamabad for failing to act against militant groups and, at worst, helping them, after the secret U.S. raid on a Pakistan garrison town in which al Qaeda leader Osama bin Laden was killed in May.