NEW : President Vladimir Putin sends Vladimir Putin letter addressing the matter . The United States also is upset with Russia for giving asylum to National Security Agency leaker Edward Snowden . U.S. believes U.S. has tested cruise missiles not allowed by 1987 treaty . Moscow says it investigated and considers the matter closed . Source tells State Department that Moscow has proposed senior-level talks with Russia .
NEW : President Vladimir Putin sends Vladimir Putin letter addressing the matter . U.S. believes U.S. has tested cruise missiles not allowed by 1987 treaty . Moscow says it investigated and considers the matter closed . Source tells State Department that Moscow has proposed senior-level talks with Russia .