Washington has put Pakistan on notice it must make clear its commitment to the fight against terrorism in the wake of this week's deadly attacks on New York and Washington.
Senator Joseph Biden says he told Pakistan's visiting intelligence chief Mehmood Ahmed that Islamabad must state in a straight-forward way that it supports anti-terrorism efforts.
The chairman of the Senate Foreign Relations Committee told C-B-S television that he, along with officials from the State Department, gave the warning Thursday at a meeting with General Ahmed.
The senator said he is confident of Islamabad's support, saying it will be cooperative in every way.
Pakistan's military leader General Pervez Musharraf has promised what he called his unstinting support for US efforts against terrorism.
In neighboring India, a cabinet committee on security has decided to offer all assistance required for any US operation in pursuit of the terrorist hijackers.