Russia categorically denied plans to invade Ukraine on Monday, accusing the US of “whipping up hysteria” and “provoking escalation” of a military conflict between the two countries for its own “pernicious interests.”

“Discussion about the threat of war is provocative in and of itself,” Russian Ambassador Vasily Nebenzya said during his opening remarks to the United Nations Security Council on Monday. “You almost seem to be calling for it, as if you want it to happen, as if you want your words to become a reality.” The US requested the Security Council meeting in response to Russia’s recent buildup of more than 100,000 troops along Ukraine’s border, which the US and NATO allies see as a precursor to an invasion of the independent country.

U.S. Ambassador Linda Thomas-Greenfield told Security Council members that Russia’s actions constituted “the largest mobilization of troops in Europe in decades” and warned that “if Russia continues to invade Ukraine, none of us will be able to say we didn’t see it coming.” And the ramifications will be horrifying.”

Nebenzya, on the other hand, downplayed the significance of the Russian military’s recent movements, insisting that 100,000 troops have been deployed along the Ukrainian border “is not the case.”

“We have never cited that figure, never confirmed that figure,” he said, attempting to compare Thomas-remarks Greenfield’s to Secretary of State Colin Powell’s now-infamous speech to the Security Council ahead of the United States’ invasion of Iraq in 2003, in which he incorrectly claimed that Saddam Hussein was developing weapons of mass destruction.

“They didn’t find any weapons,” Nebenzya explained, “but what happened in that country is well known to everyone.”

While the United States and its NATO allies have repeatedly expressed support for Ukraine’s right to self-determination and vowed to act swiftly if Russia launches an attack, Nebenzya accused the West of “attempting to drive a wedge between Russia and Ukraine.”

The public confrontation on Monday comes after weeks of diplomatic efforts to deescalate tensions. Last week, the United States and NATO issued written responses to a number of security demands made by the Kremlin. While Secretary of State Antony Blinken stated that the document produced by Washington offered Russia “a diplomatic path forward,” he made it clear that this path did not include concessions on the Kremlin’s main demands, such as the withdrawal of NATO troops from Eastern Europe and the guarantee that Ukraine and other former Soviet-bloc countries would be barred from joining the alliance.

On Monday, Thomas-Greenfield questioned Moscow’s commitment to finding a peaceful solution to its stated security concerns, saying that “if this is truly about Russia’s security concerns in Europe, we’re offering them the opportunity to discuss those concerns at the negotiating table.”

“If they refuse,” she went on, “the world will know why and who is to blame.”

Despite the heated exchange, Thomas-Greenfield reiterated the Biden administration’s position that the US “believes there is a diplomatic path out of the crisis caused by Russia’s unprovoked military buildup.”

“We continue to hope that Russia will choose diplomacy over conflict in Ukraine, but we cannot simply wait and see,” she said.

In a statement, President Biden called the Security Council meeting “a critical step in rallying the world to speak out in one voice: rejecting the use of force, calling for military de-escalation, supporting diplomacy as the best path forward, and demanding accountability from every member state to refrain from military aggression against its neighbors.”