The Pentagon said on Tuesday it was concerned about the arms deal between Iran and Russia for missile systems. "On the S-300, we've long expressed our concerns of reports on this possible sale of this missile system to the Iranians. We do not see this as a positive development," said Pentagon spokesman Peter Cook. "At the same time, here at the Defense Department, again, the president will have options available to him even if that system is put into place," said Cook.

Iranian media reported that Iranian Defense Minister Hossein Dehghan announced on Tuesday an agreement had been reached with Russia for Tehran to procure the S-300 long-range surface-to-air missile systems. "The text of the contract is ready and our friends will go to Russia next week to sign the contract," Dehghan was cited as saying by Iran's Fars News Agency.

Although the U.S. is disappointed with the cooperation, Pentagon is not thrilled as Cook said "We have long expressed our concerns of reports on this possible sale of this missile system to the Iranians. We take the safety and security of our allies in the region seriously. This is something we have been tracking, and in general, we are confident in our capabilities, even if that system is sold."

Two weeks ago, Russian and Iranian naval forces staged a series of war drills in the waters near northern Iran, in a joint show of force meant to display the two nations' control of nearby waterways. The two countries praise each other's regional policies and look for ways to expand military cooperation.