Russia said on Wednesday it is open to security talks but would resolutely counter any new threats, as the expiry of its last arms control treaty with the U.S. marked the end of over half a century of limits on both sides¡¯ strategic nuclear weapons.

The ?New START treaty expired at the end of Wednesday, and Moscow said Washington had not responded to Russian President ?Vladimir Putin¡¯s proposal ?to keep observing the missile and warhead limits for another 12 months.

¡°Essentially, our ideas are ?being deliberately ignored. This (U.S.) approach appears mistaken and regrettable,¡± the Russian Foreign Ministry said in a statement.