The United States and Russia have commenced nuclear weapons talks in Vienna, with China failing to send a representative despite an open invitation from the Americans.
Talks on the current New START (Strategic Arms Reduction Treaty) will see US arms control envoy Marshall Billingslea and other officials meet Russian deputy foreign minister Sergei Ryabkov in Austria's capital.
Due to expire next February, 2010's New START accord is the last remaining pact limiting nuclear proliferation between Russian and the US.
As it stands, both countries are limited to the deployment of 1,550 strategic nuclear weapons each.
President Donald Trump has repeatedly called for China to join discussions for a new three-way replacement deal.
Thought to possess 300 nuclear weapons, China has held firm on its refusal to partake.
Mr Billingslea expressed his disappointment on Twitter, accusing Beijing of a secret "crash nuclear build-up".
This week's talks come amid growing concern the US and Russia see little value in arms control.
Donald Trump has already scrapped security treaties with Russia during his time in administration.
The deadlock over New START and the demise of other nuclear arms control treaties "suggest that the era of bilateral nuclear arms control agreements between Russia and the USA might be coming to an end," said Shannon Kile, arms control expert at the Stockholm International Peace Research Institute.
According to the institute's latest research, Russia has 6,375 nuclear warheads, including those that are not deployed, and the United States has 5,800.
China meanwhile has 320 warheads.
With little to to either renew the New START deal or negotiate a new deal altogether, Russia's Mr Ryabkov said on the weekend an extension on the current would be "correct and logical" but the future of the world does not depend on it.
Cover image: Military personnel observing one of the tests in the Buster-Jangle Series in 1951 (Picture: US Department of Defense).