U.S. ratification of the Comprehensive Nuclear Test Ban Treaty (CTBT) will speed up the document’s entry into force, the speaker of the upper house of the Russian parliament said on Wednesday.

"Naturally, we are worried by the lack of progress in the ratification of the Comprehensive Nuclear Test Ban Treaty. We are convinced that the treaty’s ratification by the U.S. would significantly speed up the process of the document coming into force,” Federation Council Speaker Valentina Matviyenko said at a nuclear conference in the Kazakh capital Astana.

She said Russia’s proposal on a treaty to ban the deployment of weapons in space “is being blocked by certain Western states.”

Adopted by the U.N. General Assembly in 1996, the CTBT is yet to come into force. It has been signed by 183 and ratified by 157 countries, but major nuclear powers either refused to sign (India) or failed to ratify (U.S. and China). The U.S. Senate rejected the treaty in 1999.

In 2006, the UN General Assembly ratified a resolution supporting the CTBT entry into force.

Under Secretary of State for Arms Control and International Security Ellen Tauscher said in mid-February the treaty’s ratification remains one of the priorities of U.S. foreign policy.