Russian Foreign Minister Sergei Lavrov has repeated the Kremlin's demands for solid legal guarantees that a U.S. missile defense system for Europe does not target Russia.

Lavrov told the United Nations General Assembly Tuesday Russia wants assurances that missile defense will met its declared objectives and not disrupt global and regional balances.

He said the issue is too serious and that statements guaranteeing strategic balances are not enough. He said this includes the Asia-Pacific region, where he said ballistic missile defense is becoming a factor.

The United States wants to build a land- and sea-based missile defense system to protect NATO and its allies against a possible attack from Iran or North Korea. It insists the missile shield is purely defensive and not aimed at Russia or anyone else.

Russia has said such a system would upset its own nuclear deterrent as well as the strategic weapons balance in Europe.