The United States has called Russia's decision to suspend a cooperative program that commits the two countries to eliminating parts of their weapon-grade plutonium stocks "a big mistake."
State Department spokesman Joshua Baker told RFE/RL's Current Time TV on October 4 that the agreement "was about cooperation in the sphere of nuclear security," adding that the United States would like that cooperation "to continue."
President Vladimir Putin suspended the deal on October 3, before Washington announced it was suspending talks with Russia on trying to end the violence in Syria.
WATCH: What Is The U.S.-Russia Plutonium Management
"[Moscow and Damascus] did not want a truce, they did not want agreements, they did not want cessation of violent actions," Baker said. "That is exactly why we considered that it would be better for the United States to focus mainly on humanitarian assistance and closer cooperation with our other partners in Syria."
In a bill submitted to parliament on October 3, Putin sets pre-conditions for the nuclear accord to be resumed -- including lifting all U.S. sanctions against Russia and compensation for the damage they have caused, and reducing U.S. military infrastructure and troops in Eastern Europe.
Baker said the sanctions imposed on Russia over its actions in Ukraine will remain until the Minsk agreements aimed at putting an end to fighting between government forces and Russia-backed separatists in eastern Ukraine are fulfilled.
He said Moscow should also return the annexed Crimean Peninsula to Ukraine.