“Before launching missile defense projects, we need to have firm judicial assurances that the US missile defense system will not be used against Russian nuclear deterrence forces,” he said adding that Moscow “does not have enough predictability regarding the US and NATO missile defense plans.”Shoigu also stressed that “mutually beneficial cooperation” would contribute to the strengthening of each state’s security.

NATO Secretary General Anders Fogh Rasmussen said: “It is no secret that we have not yet found the way to work together [in this area].” But “ministerial discussions are valuable in addressing existing concerns, and we need to continue to engage frankly and directly to overcome our differences.”

The US missile defense system in Europe, which NATO and the US say is aimed at countering threats from North Korea and Iran, has been a particular source of friction in US-Russian relations for a number of years.

Russia and NATO formally agreed to cooperate over the European missile defense system at the 2010 NATO summit in Lisbon, but talks foundered, in part over Russian demands for legal guarantees that the system would not target its strategic nuclear deterrent.

In mid-March, the US announced that it was modifying its planned missile defense deployment to Poland, dropping plans to station SM-3 IIB interceptors in the country by 2022.