On Monday, Feb. 21, the crisis at the border between Russia and Ukraine escalated to a new high. Russian officials claimed that they killed five Ukrainians who crossed the border to attack Russian troops. Ukrainian Foreign Minister Dmytro Kuleba strongly denied these claims, stating in a tweet, “Ukraine did NOT: attack Donetsk of Luhansk, send saboteurs or APCs over the Russian border, shell Russian territory, shell Russian border crossing, conduct acts of sabotage.”

This recent development is the biggest in the Russia-Ukraine news since this weekend, when tensions seemed to relax. However, with Russia stating that they have slain five Ukrainians, officials across the globe worry that they are gearing up to attack. Leaders are currently trying to push for a summit that would include U.S. President Joe Biden and Russian President Vladimir Putin. Both leaders have cautiously agreed to meet.

U.S. officials have said the meeting will only occur if Russia does not invade Ukraine, and Dmitry Peskov, a spokesman for the Russian government, stated that it would be “premature” to discuss specifics of a summit. On Thursday, the U.S. Secretary of State and the Russian Foreign Minister are to meet and discuss the terms of a possible meeting between the two leaders.

Tensions between Russia and Ukraine escalated in 2014, when Russia annexed the Crimean Peninsula from Ukraine. Since then, the two countries have been fighting both diplomatically and physically, causing at least 14,000 deaths.

Russian troops have been carrying military exercises out in Belarus, which borders Ukraine to the north. Last week, Putin said that Russian troops were withdrawing, and provided videos of troops and gear pulling out on trains. On Sunday, Russia extended the military exercises and announced that troops would not pull out. The troops are stationed close to the border, only about a three-hour drive from the Ukrainian capital city of Kyiv.

The European Union has agreed to set up a military education advisory mission in Ukraine, according to Ukrainian Foreign Minister Dmytro Kuleba. This mission will serve to train Ukrainians in military strategy. It could also send European officers to existing military schools in Ukraine to educate their armed forces. Details are still being decided, but the mission will likely take several months to set up.

Many top UN officials are preparing their countries for Russia to breach Ukraine’s borders. “Diplomacy must be pursued, but a Russian invasion of Ukraine looks highly likely,” said U.K. Foreign Secretary Liz Truss in a tweet on Monday. “The UK and allies are stepping up preparations for the worst case scenario. We must make the cost for Russia intolerably high.”

The United States is also prepared for the worst case scenario, with Biden tweeting, “The West is united and resolved- and we are ready to impose severe sanctions on Russia if it further invades Ukraine.” 

The U.S. has also begun to evacuate its embassy in Kyiv, following the actions of other countries in the U.N. Embassies will keep a small number of diplomats, but non-essential staff and other private American citizens are urged to leave.