Dmitry Medvedev, the Russian president, has warned that a new arms race could erupt if Russia and the West could not agree on building a missile defence system.
Speaking at his annual state of the nation address on Tuesday, Medvedev said questions remained about the proposed missile shield, which Russia has agreed to work on with Nato.
"In the coming decade we face the following alternatives: Either we reach agreement on missile defence and create a full-fledged joint mechanism of co-operation, or ... a new round of the arms race will begin," he said.
"And we will have to take a decision about the deployment of new offensive weapons. It is clear that this scenario would be very grave."
Earlier this month Russia and Nato agreed in Lisbon to look into ways in which the two could work together on a new continental shield, which the Kremlin has spent years resisting.