Iran's defence minister has said its forces will confront any US aircraft that attempts to use its airspace during strikes on neighbouring Afghanistan.
Though Iran, branded a sponsor of terrorism by the US, has condemned last month's attacks it has ruled out co-operating on retaliatory strikes.
"We are military men, we don't joke with anyone. Mistakes cannot be repeated. If it is repeated, it means it is planned and we will confront them, we will defend our airspace," Admiral Ali Shamkhani said.
"Their military deployments in the region shows they are going to stay and this worries us," Admiral Shamkhani said who is due to meet Russian Defence Minister Sergei Ivanov on tomorrow.
Despite Iran's unease about U.S. military moves, the Shi'ite Islamic Republic is not an ally of the Taliban, which is Sunni. It believes their fundamentalist beliefs are primitive and give Islam a bad name.
Shamkhani confirmed for the first time that Iran has provided arms to the anti-Taliban Northern Alliance and he said it would continue to do so.
"We always co-operated with them from the beginning," he said. "Our co-operation with the Northern Alliance is not related to this crisis... We used to give them arms and we will continue to do so," he said.