President Joe Biden spoke for an hour with Russian President Vladimir Putin on Saturday. He said that Ukraine’s invasion would lead to “widespread suffering” and that the West was ready to engage in diplomacy to resolve the crisis. The White House stated that they were also prepared for “other scenarios”. It did not suggest that the call reduced the danger of war in Europe.

Biden’s national security advisor Jake Sullivan warned that a Russian invasion could be imminent within days.

Russia denies that it intends to invade, but has gathered well over 100,000 troops close to the Ukrainian border and sent troops to exercise in Belarus. Officials from the United States claim that Russia’s firepower is at a point where it can invade quickly.

KLM, a Dutch airline, has cancelled flights to Ukraine for now.

After the shooting down of a Malaysian aircraft over eastern Ukraine, where Russia-backed rebels held it, Dutch sensibility to possible danger in Ukrainian airspace has been high. All 298 people aboard died, including 198 Dutch citizens.

SkyUp, a Ukrainian charter airline, stated Sunday that its flight from Madeira (Portugal) to Kyiv was diverted via Chisinau, Moldova, after an Irish lessor claimed it was banning flights into Ukrainian airspace.

Serhii Nykyforov, the Ukrainian presidential spokesperson, told The Associated Press that Ukraine had not closed its airspace. The Infrastructure Ministry stated that “Some carriers are having difficulties due to fluctuations in the insurance market.”

After a call between Putin, French President Emmanuel Macron, the Putin-Biden phone call came at a crucial moment in what has become the most serious security crisis between Russia’s and the West since the Cold War. Officials in the United States believe that they have only days to stop an invasion of Ukraine and massive bloodshed.

The U.S. and NATO allies do not plan to send troops to Ukraine in order to defeat Russia. However, an invasion and punishing sanctions could have reverberating effects far beyond the former Soviet Republic, affecting energy supplies and the power balance within Europe.

“President Biden made it clear to President Putin that the United States is ready to engage in diplomacy in full coordination and with our Allies, but we are equally prepared for any other scenario,” stated the White House.

Putin’s top foreign policy advisor, Yuri Ushakov said that tensions have been increasing for months but “the situation has just been brought to absurdity”.

Biden was mentioned by him, but he said that this issue was not the main focus of their lengthy conversation.

The United States announced plans for the evacuation of most of its staff at the Ukrainian embassy. It also urged citizens living in Ukraine to flee the country. Britain joined other European countries in urging its citizens to flee Ukraine.

Canada has closed its Kyiv embassy and moved its diplomat staff to Lviv, in the west part of the country. Foreign Affairs Minister Melanie Joly announced Saturday. Lviv is the home of a Ukrainian military base, which has been the hub for Canada’s 200-soldier soldier training mission in the former Soviet Union.

Volodymyr Zelenskyy, President of Ukraine, has downplayed fears about an invasion and urged the country to stay calm.

He stated Saturday that he believes there is a lot information today.

It remains to be determined when any Russian military action will take place.

According to an American official, intelligence indicating that Russia was looking at Wednesday as a target date was seized by the U.S. The unnamed official was not allowed to speak publicly, and spoke only under condition of anonymity.

The Defense Ministry summoned US Embassy’s military attache on Saturday to discuss further tensions between the U.S. and Russia. It was reported that the navy had detected an American sub-marine in Russian waters close to the Kuril Islands in Pacific. The ministry stated that the submarine refused to leave but left after the navy used an unspecified “appropriate method”.

To add to the crisis, the Pentagon sent 3,000 additional U.S. soldiers to Poland to assure allies.

The Russians also deployed special operations forces, missile, air and naval forces along the Ukraine’s southern and eastern borders. Russia has moved six amphibious assault vessels into the Black Sea this week, increasing its ability to land marines along the coast.

As a reassurance to NATO’s eastern flank allies, Biden has increased the U.S. military presence. These additional soldiers are joining 1,700 already on their way to Poland. The U.S. Army is also moving 1,000 soldiers from Germany into Romania. Romania shares a border to Ukraine, like Poland.

Russia demands that NATO keep ex-Soviet countries out. Russia also demands that NATO refrain from deploying weapons close to its borders and reduce the number of alliance forces from Eastern Europe. These requests are flatly rejected.

Since 2014, Ukraine’s Kremlin-friendly leader was forced from power by a popular uprising. Russia and Ukraine are locked in bitter conflict. Moscow responded by annexed the Crimean Peninsula, and then supported a separatist insurgency within eastern Ukraine where over 14,000 people have been killed.

France and Germany brokered a 2015 peace agreement that helped to end large-scale fighting. However, regular skirmishes continue and attempts to reach a political solution have been thwarted.