By Jim Heintz And Aamer Madhani

President Joe Biden told Russia’s Vladimir Putin that invading Ukraine would cause “widespread human suffering” and that the West was committed to diplomacy to end the crisis but “equally prepared for other scenarios,” the White House said Saturday. It offered no suggestion that the hourlong call diminished the threat of an imminent war in Europe.

Biden also said the United States and its allies would respond “decisively and impose swift and severe costs” if the Kremlin attacked its neighbor, according to the White House.

The two presidents spoke a day after Biden’s national security adviser, Jake Sullivan, warned that U.S. intelligence shows a Russian invasion could begin within days and before the Winter Olympics in Beijing end on Feb. 20.

Russia denies it intends to invade but has massed well over 100,000 troops near the Ukrainian border and has sent troops to exercises in neighboring Belarus, encircling Ukraine on three sides. U.S. officials say Russia’s buildup of firepower has reached the point where it could invade on short notice.

The conversation came at a critical moment for what has become the biggest security crisis between Russia and the West since the Cold War. U.S. officials believe they have mere days to prevent an invasion and enormous bloodshed in Ukraine. And while the U.S. and its NATO allies have no plans to send troops to Ukraine to fight Russia, an invasion and resulting punishing sanctions could reverberate far beyond the former Soviet republic, affecting energy supplies, global markets and the power balance in Europe.

Originally published at AP