Russian Defence Minister Sergei Shoigu spoke with U.S. Defense Secretary Lloyd Austin on Sunday for the second time in three days and held a flurry of calls with three other counterparts from NATO countries.
Moscow provided no details on the conversation with Austin, which came after the two men spoke on Friday for the first time since May. Its readouts on the other calls said Shoigu had said the situation in Ukraine was worsening.
"They discussed the situation in Ukraine which is rapidly deteriorating," the Russian defence ministry said of Shoigu's call with French Defence Minister Sebastien Lecornu. "It is trending towards further uncontrolled escalation."
Shoigu spoke separately to Turkey's defence minister, Hulusi Akar, and Britain's Ben Wallace.
Shoigu's ministry said he had told his French, Turkish and British counterparts of Moscow's concern that Ukraine could detonate a "dirty bomb" - a device laced with radioactive material. Russia has provided no evidence to substantiate such a claim.
Previous Russian assertions that Ukraine might resort to using banned weapons such as biological arms have stirred concerns in the West that Moscow might be preparing to stage "false flag" attacks and blame them on Kyiv.
The Pentagon's readout of the call said Austin told Shoigu he "rejected any pretext for Russian escalation." Austin also "reaffirmed the value of continued communication."
The White House National Security Council in a statement said it rejected Shoigu's false allegations that Ukraine is preparing to use a dirty bomb on its own territory.
"The world would see through any attempt to use this allegation as a pretext for escalation," it said.
CHANNELS OF COMMUNICATION
There was no indication from the Russian side that the conversations had produced any positive results. They showed, however, that Russia and members of the U.S.-led NATO alliance are actively maintaining channels of communication at a time of rising international concern about a possible nuclear escalation.
With Russia reeling from successive defeats in Ukraine, President Vladimir Putin has said it would resort to nuclear weapons if necessary to defend its "territorial integrity." U.S. President Joe Biden has said that the world is closer to "Armageddon" than at any time since the 1962 Cuban Missile Crisis.
NATO last week launched its annual nuclear deterrence exercise and has said it expects Russia to hold drills shortly to test the readiness of its own nuclear forces.
A top Russian diplomat was quoted after the Shoigu-Austin call on Friday as saying that "misunderstandings must be cleared up so that there are no accidents."
Lecornu after Sunday's call said he had reaffirmed France's desire for a peaceful resolution to the war in Ukraine, and that Paris refused to get drawn into any form of escalation.
Britain said Wallace had "refuted" claims by Shoigu that Western countries were facilitating a plan by Kyiv to escalate the conflict.
(Reporting by Reuters; Editing by Gareth Jones and Mark Porter)
