WASHINGTON

Russia is seeking to increase its troop presence in Belarus six-fold by early February to 30,000 armed forces, the US said on Monday during a heated UN Security Council session on simmering Ukraine tensions.

Addressing the council, Linda Thomas-Greenfield, Washington's UN envoy, said Russia has already deployed 5,000 troops to Belarus alongside short-range ballistic missiles, special forces, and anti-aircraft batteries, and has stationed well over 100,000 troops inside its border near Ukraine.

All told, Thomas-Greenfield said the Kremlin is engaging in an "escalation in a pattern of aggression that we’ve seen" repeatedly, citing its 2008 invasion of Georgia and its 2014 invasion and annexation of Ukraine's Crimean Peninsula.

"If Russia further invades Ukraine, none of us will be able to say we didn’t see it coming. And the consequences will be horrific," she told the Security Council.

"Already, Russia’s war in eastern Ukraine has killed more than 14,000 Ukrainians. Nearly 3 million Ukrainians – half of whom are elderly people and children – need food, shelter, and lifesaving assistance. Devastating as this situation is, it would pale in comparison to the humanitarian impact of the full-scale land invasion Russia is currently planning in Ukraine," she added.

The ambassador was referring to Moscow's ongoing support for separatist rebels in eastern Ukraine that began in 2014, and which has continued over the course of the past eight years.

The council's public meeting came at the request of the US, and overcame a Russian procedural attempt to scuttle it just ahead of the open debate.

Vasily Nebenzya, Russia's UN ambassador, accused the US of launching "unfounded accusations" over a potential Russian invasion of Ukraine, and attempting to "whip up hysterics."

“The deployment of Russian troops within our own territory has frequently occurred on varying scales before, and has not caused any hysterics whatsoever," he said.

He further called into question the US' estimate of 100,000 troops stationed in Russian territory on the Ukrainian border, saying "that is not the case," and maintaining Russia has "never confirmed that figure."

Russia's attempts to dismiss concerns over a potential invasion were quickly rejected by Ukrainian envoy Sergiy Kyslytsya who said the international community continues to "lack credible explanations" from Russia over its "actions and military movement."

Thomas-Greenfield, the US's UN diplomat, echoed Kyslytsya, maintaining Russia's "actions will speak for themselves."

"Our recognition of the facts on the ground is not provocative. The threats of action if Russia’s security demands aren’t met is provocative," she said.

Russia demanded in December that NATO limit its troops and weapons in Eastern Europe, and guarantee Ukraine not be allowed membership in the alliance in order to diffuse ongoing tensions.

NATO and the US rejected the proposals, and Ukraine's UN envoy rebuffed Russia's call for Ukraine to be barred from NATO membership, saying it is Kiyv's "inherent sovereign right" to choose Ukraine's security arrangements, including potential membership in the transatlantic alliance.

"This right is enshrined in many international legal instruments that Russia itself is a party to. Ukraine will not bow to threats aimed at weakening Ukraine, undermining its economic and financial stability, and inciting public frustration," he said.