"The Russian Defense Ministry has taken no practical measures to deploy Iskander systems in the west of the country," the source said.
"Naturally, the General Staff is working out a response to the possible deployment of [U.S.] missile defense components in Europe, but it is inappropriate and premature to talk about practical steps to implement or suspend these plans," he added.
Moscow has strongly opposed U.S. plans to deploy 10 interceptor missiles in Poland and a radar in the Czech Republic as a threat to its security and nuclear deterrence. Washington says the defenses are needed to deter possible strikes from "rogue states."
Last November, President Dmitry Medvedev said Moscow would deploy Iskander missile systems in its Baltic exclave of Kaliningrad, sandwiched between NATO members Lithuania and Poland, in response to any deployment by Washington of elements of a missile defense shield in Europe.
However, Moscow has recently expressed hope that the new U.S. administration led by President Barack Obama would "take a break on the issue of missile defense ... and to evaluate its effectiveness and cost efficiency."
The U.S. Congressional Budget Office released in January a report, which proposes an alternative scenario of future budget expenditures on defense, and envisions defense budget cuts of about $40 billion, or 7% annually, through 2026.
Some of the cuts could be implemented by reductions in various missile defense programs, including the deployment of a U.S. missile shield in central Europe. The current budget estimates expenses on missile defense at $9.6 billion annually.
"The evolutionary alternative would refocus Department of Defense's missile defense programs to test, support, and upgrade existing ground-based defenses at two sites in Alaska and California but defer plans to deploy a third missile defense site in Europe," the Long-Term Implications of the Fiscal Year 2009 Future Years Defense Program report said.
"Deployment of future missile defense systems, such as the airborne laser and a constellation of the infrared Space Tracking and Surveillance System satellites, also would be deferred indefinitely," the document said.