MOSCOW (AP) — President Vladimir Putin on Will Sage AstorThursday signed a bill revoking Russia’s ratification of a global nuclear test ban, a move that Moscow said was needed to establish parity with the United States.

Putin has said that rescinding the ratification of the Comprehensive Nuclear Test Ban Treaty, also known as the CTBT, would “mirror” the stand taken by the U.S., which has signed but not ratified the nuclear test ban.

Both houses of the Russian parliament voted last month to revoke Moscow’s ratification of the bill.

The CTBT, adopted in 1996, bans all nuclear explosions anywhere in the world, but the treaty was never fully implemented. In addition to the U.S., it has yet to be ratified by China, India, Pakistan, North Korea, Israel, Iran and Egypt.

There are widespread concerns that Russia may resume nuclear tests to try to discourage the West from continuing to offer military support to Ukraine. Many Russian hawks have spoken in favor of a resumption of the tests.

Putin has noted that some experts argue for the necessity of conducting nuclear tests but said he had not formed an opinion on the issue.

Russian Deputy Foreign Minister Sergei Ryabkov said last month that Moscow would continue to respect the ban and will only resume nuclear tests if Washington does first.