Russia may be paving the way to conduct a nuclear test, a move that would sharply raise tensions with the West and likely prompt other world powers to resume testing for the first time this century.
President Vladimir Putin last week said Russia's parliament should consider withdrawing Moscow's ratification of the 1996 Comprehensive Test Ban Treaty (CTBT), which prohibits tests involving nuclear explosions. Parliamentary leaders were due to discuss the issue on Monday.
Some Western security analysts now see a growing likelihood of a Russian test, even though Putin said the aim was only to mirror the position of the United States, which has signed but not ratified the treaty.