The S-300 anti-aircraft missile system at the Victory Parade, Red Square, 2009. Photo: Wikipedia.

The Pentagon expressed disapproval over an emerging Russian missile system deal with Iran, The Hill reported on Tuesday.

Pentagon Press Secretary Peter Cook said the U.S. did not see this “as a positive development,” but noted that the U.S. still had “options” once the contract goes through.

Russian news agency Interfax reported on Wednesday according to a “source with knowledge of the situation” that the contract to sell Russian S-300 surface-to-air missile defense systems was weeks or even days away from being signed, though the original deal was signed in 2007.

Iranian Defense Minister Hossein Dehghan also indicated that the sale was near completion.

According to The Hill, Russia offered Iran a different model of the S-300 system,  the S-300VM, to help avoid a $4 billion Iranian lawsuit against Moscow for failing to complete the 2007 deal. Interfax also reported that Iran had agreed to drop its claims.

The VM can strike aircraft more than 120 miles away as well as intercept ballistic missiles within a 25 mile range. Using radar, the portable systems can detect some 200 aerial targets up to 150 miles away.

The system would be able to detect an impending attack, and if they were deployed Iran could be alerted to attempted airstrikes on its nuclear facilities. The systems could also be used to harass non-hostile aircraft in neighboring countries.

Cook insisted the U.S. still had options to deal with the eventuality of Iran’s getting this missile system, but he would not elaborate further.

Also this week, Russian President Vladimir Putin hosted leaders from Jordan, Egypt and the Untied Arab Emirates at an air show in Moscow, where he said many “serious agreements” were reached regarding a coalition to combat regional terrorist threats like ISIS and resolving the civil war in Syria, where Moscow is one of Syrian President Bashar al-Assad’s last remaining allies.