The US on Monday announced an additional $457 million in aid to Ukraine, a day after White House National Security Adviser Jake Sullivan warned of “catastrophic consequences” if Russia were to use nuclear weapons.
The State Department said the money will be used to help Ukrainian law enforcement and criminal justice agencies, and that a portion of the funding will be aimed at supporting the Ukrainian government’s efforts to document, investigate and prosecute Russian “atrocities”.
The announcement comes after Russian President Vladimir Putin stepped up his nuclear rhetoric in the seven-month-old conflict, saying that Moscow was prepared to use “all the means at our disposal” if Russia's territorial integrity is threatened.
This “is not a bluff”, he said last week.
Mr Sullivan on Sunday told US news networks that if Russia were to cross that line, the results would be calamitous for Moscow.
“If Russia crosses this line, there will be catastrophic consequences for Russia. The United States will respond decisively,” Mr Sullivan told NBC's Meet the Press.
White House Press Secretary Karine Jean-Pierre on Monday said the US does not see substantial evidence of an increased nuclear threat.
"We take these threats very seriously. But we have not seen any reason to adjust our own nuclear posture at this time," said Ms Jean-Pierre.
Ukrainian President Volodymyr Zelenskyy also took to American television on Sunday to reiterate that Mr Putin's threats should not go unheeded.
“I don't think he's bluffing. I think the world is deterring it and containing this threat. We need to keep putting pressure on him and not allow him to continue,” Mr Zelenskyy told CBS's Face the Nation.
He also called on Washington to add Russia to its list of state sponsors of terrorism following the discovery of new evidence of alleged Russian atrocities in recently liberated Izyum.
The head of regional military administration in Ukraine's Kharkiv region said officials had exhumed 436 bodies, including 30 with signs of torture, from a mass burial site near the eastern city of Izyum last week after forces recaptured it from Russian occupation.
“The United States could show its leadership position and recognise Russia as a sponsor of terrorism,” said the Ukrainian president.
“I understand there will be implications. These implications will make diplomatic negotiations impossible — however, they are terrorists and we cannot let them do it out of fear.”
Earlier this month, White House National Security Council communications co-ordinator John Kirby told reporters that the administration of US President Joe Biden did not see that designation as a viable option.
“We just don't believe that it's the most effective, quite frankly, the strongest way to hold Russia accountable,” Mr Kirby told reporters.
He said some humanitarian experts and NGOs had warned the State Department that a terror designation would make it harder to get aid into Ukraine.
“We also think it could undercut our multilateral co-ordination, about holding Putin accountable,” he added.
Cuba, North Korea, Iran and Syria are the only countries currently on Washington's terrorism sponsor list.
Monday's announcement of $457.5m in extra funds comes on top of more than $15 billion in military aid the US has already sent Ukraine. The US has also approved billions more in non-military assistance.
New polling from Pew Research has shown that the American public's concern for the Russia-Ukraine war has waned.
The share of US adults who are “extremely” or “very concerned” about a Ukrainian defeat is down 17 percentage points since May, from 55 per cent then to 38 per cent. Roughly a quarter — 26 per cent — said they are not too concerned or not at all concerned about Russia defeating Ukraine, up from 16 per cent earlier this year.
