"We are ready to receive and discuss any feasible proposal, which takes into account Russia's concerns about the shift in strategic balance," Makarov said after a meeting with the NATO chiefs of staff.

Russia and NATO agreed to cooperate on the so-called European missile shield during the NATO-Russia Council summit in Lisbon in November 2010. NATO insists there should be two independent systems that exchange information, while Russia favors a joint system with full-scale interoperability.

Makarov said he had reiterated Russia's proposal to provide a "missile shield" over Eastern Europe, the Black, Barents and Baltic seas.

Russia has retained staunch opposition to the planned deployment of U.S. missile defense systems near its borders, claiming they would be a security threat. NATO and the United States insist that the shield would defend NATO members against missiles from North Korea and Iran and would not be directed at Russia.

Bucharest announced on Tuesday that it had reached an agreement with the United States to deploy a U.S. missile interceptor system at a defunct Soviet airbase on its territory. Moscow issued an urgent request for legal guarantees from the United States that the system will not target Russia's strategic nuclear forces.

"We are set to demand maximum guarantees that the European missile system is not directed against Russia's nuclear potential," Makarov said. "We are waiting for NATO proposals and hope for understanding with our European colleagues."