Linda Thomas-Greenfield, the US ambassador to the UN, said on Monday that 127,000 Russian troops are now positioned along Ukraine’s border.
Her estimate confirms that of the Ukrainian defence ministry, which last week said Russia had “almost completed” its build-up for an attack. The number is higher than recent estimates that have said about 100,000 Russian troops are now at the border.
"We see 127,000 troops building up along the border. We have seen that the Russians have put troops in motion,” Ms Thomas-Greenfield told reporters.
She described Russia’s escalation as part of Moscow's usual strategic tactics.
“While we can't predict exactly what will happen next, we know Russia's playbook,” the US ambassador said.
“We know it includes measures beyond overt military action. It often starts with cyber attacks, paramilitary activity, disinformation campaigns intended to obscure the facts and create a pretext for their own aggression, and other efforts to destabilise their target."
Asked about the updated US rules ordering relatives of its Kiev embassy staff to leave and an advisory urging American citizens to depart Ukraine, Ms Thomas-Greenfield said the development comes amid a worsening situation.
“We have an obligation to protect our staff. And we've been very, very clear that we see the situation deteriorating, and we want to make sure that we put our staff in a place where they feel protected,” she said.
She also committed to pursuing diplomacy with Moscow.
“We are continuing to pursue the path of diplomacy and dialogue and we have made clear we need to see signs of de-escalation from Russia,” she said.
Ms Thomas-Greenfield did not foresee a UN peacekeeping force in Ukraine.
“That is a decision that will be made in the context of how the Security Council decides to engage on this issue. But as far as I know, no one has discussed the possibility of peacekeeping force in Ukraine,” she said.
No meeting from the Security Council on the situation in Ukraine has been tabled either. Permanent member Russia holds a veto vote on Security Council decisions.