The latest American warnings do not say who might carry out a new terrorist attack.
In the past, Iranian ships and aircraft have generally heeded American warnings.
The reported Iraqi movements and the American warning came at a time of renewed tension in the north.
Brazilian officials, however, have contested American warnings about that situation and maintain that their country does not confront any threat of terrorism.
Strong American warnings have probably helped deter fresh coup attempts.
American warnings that we are serious about Kosovo are no longer credible.
It is the first direct American military warning to Iran in recent years.
Iraq sent helicopters to the Saudi border to pick up religious pilgrims today in defiance of American warnings.
They came despite strong American warnings to stay out.
But they have also criticized the American warnings.