"This is something that is of concern to us and concern to Iran's neighbours. On the one hand, every country is sovereign and has the right to provide for its own self-defense, but obviously, we take into account systems that can potentially threaten particular countries or peace and stability in the region more broadly," state department spokesman P J Crowley said.
"But in the face of growth of Iran's capabilities over a number of years, we've stepped up our military cooperation with other countries in the region, and this is one of the reasons why we believe that if Iran continues on the path that it's on, it might actually find itself less secure because you'll have countries in the region that have joined together to offset Iran's growing capabilities," he said.
Noting that there's no particular logic to the path that Iran is on, Crowley said its nuclear ambitions, the US believes, will actually make Iran less secure in the long run.
"We're still open to constructive dialogue with Iran to try to clarify the questions that we have and the international community has about the true nature of its nuclear programs. But in the meantime, we will work with other countries to try to do everything that we can to maintain peace and stability in the region," Crowley said.