Iran will respond firmly to any US threat against it, the semi-official Tasnim news agency reported on Saturday, citing foreign ministry spokesman Abbas Mousavi.
"We will not allow any violation against Iran's borders. Iran will firmly confront any aggression or threat by America," he was quoted as saying.
Tension between Tehran and Washington has spiked since Thursday when an Iranian missile destroyed a US Global Hawk surveillance drone. Tehran said the drone was shot down over its territory and Washington said it occurred in international airspace.