WASHINGTON, July 26 (Reuters) - The United States and Russia blamed each other for a lack of progress on arms control following a US proposal to open talks on a "framework" that would preserve curbs on strategic nuclear weapons deployments when the current limits expire in 2026.
Russia's apparent rejection of the plan last week and what several arms control experts say was a White House failure to formally convey it to Moscow have fuelled concerns about whether there would be enough time to reach a new pact.
"There is no excuse that the administration has delayed for nearly two months the formal communication of this proposal to the Kremlin," said Daryl Kimball, executive director of the Arms Control Association (ACA) advocacy group.
Such complex negotiations would be "difficult in good times and extraordinarily difficult so long as Russia's war on Ukraine continues," he said.
US President Joe Biden's national security adviser Jake Sullivan unveiled the proposal in a Jun 2 speech to the ACA, announcing that the administration was ready for talks "without preconditions" with Moscow on managing "nuclear risks" and "a framework" to replace the New START treaty after it expires.
Sullivan said that any new limits to which Washington could agree would be "impacted by the size and scale" of China's ongoing nuclear arsenal buildup.
Russia last Friday appeared to reject the US proposal. The state-run TASS news agency quoted Deputy Foreign Minister Sergei Ryabkov as saying that while Moscow studied Sullivan's speech, Washington had not sent a formal written proposal.
"We are not ready to and will not conduct this dialogue based on what the Americans are now proposing as they ignore several points," Ryabkov, Moscow's top arms control negotiator, said according to TASS.
A US National Security Council spokesperson said in an email that the United States "remains open to discussing nuclear risks and the future of arms control with Russia. Unfortunately the Russian side appears not to share this willingness."
Asked whether the US had delivered a formal proposal, the NSC spokesperson said Russia "was very clearly aware of Jake's speech", adding that the administration "privately" conveyed the proposal to Moscow, but he declined to elaborate.
The last US-Russia strategic arms control pact, New START capped the number of strategic nuclear warheads each side can deploy at 1,550. It also set at 700 the number of land- and submarine-based missiles and bombers that deliver them.
The US and Russia extended the 2010 pact in 2021 for five years and have continued observing its curbs despite Russia's February announcement that it was suspending participation in the accord, a move denounced by Washington as "irresponsible and illegal".
The United States on Jun 1 ended notifications required by the pact that Russia halted earlier this year.
US-Russia relations are frostier than during the Cold War over Russia's full-scale invasion of Ukraine, arms control, and other issues.
Moscow, Ryabkov said, could not discuss arms control issues divorced from other disputed matters.
"We must first and foremost make sure that the US policy, which is fundamentally hostile toward Russia, is changing for the better for us," he continued. "I would rather say that the opposite is going on."
Still, said Kimball, Ryabkov's statement seemed to leave room for eventual negotiations.
"My interpretation is that there is still scope for the US to communicate about what they are interested in," he said.
Washington does not know when Russia will be ready for talks, said the NSC spokesperson, adding that "we will continue to adapt our security to these conditions."