US Secretary of State Colin Powell says the US will hunt down the entire al Qaeda terrorist network starting with its leader Osama bin Laden.
Mr Powell believes all roads lead to bin Laden in Afghanistan and the ruling Taliban could find him if they wanted.
The Taliban say he is a guest in their country. Mr Powell says it is now time for the guest to leave.
He told a press conference America meant no ill toward people of Afghanistan, who are already suffering and poor.
Mr Powell said: "The al Qaeda network is the prime suspect and all roads lead to Osama bin Laden.
"He is the chairman of the holding company, within that company are terrorist cells and organisations in dozens of countries around the world.
"It's not enough to get one individual - although we will start with that one individual."
Mr Powell said the US will be communicating with the Taliban, but would not give further details.