What’s happening in the Ukraine-Russia crisis

The Kremlin has also sought assurances that Ukraine, which was once a Soviet state, never be allowed to join the NATO military alliance. In a Dec. 17 ultimatum presented by the Kremlin to the United States, Russia said it wanted commitments that NATO would withdraw troops from countries that joined the alliance after 1997.

The Ukrainian view: Officials in Kyiv have long criticized the Minsk peace deal, which was brokered after a series of military losses. They have said that they will support the agreement only if it is restructured.

Ukraine has said it is open to talks with Russia in a third-party country. “Ukraine stands ready for negotiations in Istanbul, as well as in Geneva, Vienna or any other place that is impartial and doesn’t depend on one of the sides, namely Russia,” Ukrainian Defense Minister Oleksiy Reznikov said last week, according to Russia’s Interfax news agency.

The Western view: The United States and other allies have said they support the 2015 Minsk deal, but called on all parties of the agreement — including Russia — to live up to their side of the bargain.

The Biden administration has rejected Russia’s demands on NATO, instead calling on Russia to pull its forces back from along the Ukrainian border and stop its support for separatists in Donbas.

Russian troops: The Kremlin began moving troops to its regions bordering Ukraine last year. Western officials say there are now more than 100,000 in the region and Crimea, a Ukrainian peninsula occupied by Russia since 2014. Military drills with ally Belarus, which also borders Ukraine, began last week.

The Biden administration believes that Russia is planning to invade, possibly after Moscow creates a pretext by broadcasting images of civilian casualties to drum up anger against Kyiv. Separately, the British government has said Russia plans to destabilize the Ukrainian government and install a pro-Russian one in its place.

The most recent U.S. assessment concluded that Russia as amassed around 70 percent of the combat forces it would need to launch a full-scale invasion of Ukraine and attack on Kyiv. Such an assault would likely be Europe’s largest land offensive since World War II.

NATO forces: The United States has responded by sending more troops to Eastern Europe, with around 3,000 troops moving to NATO’s eastern flank in Romania from their current positions in Germany and Fort Bragg. Previously, 8,500 U.S. troops were placed on heightened alert.

There have also been movements of military hardware from NATO allies, with F-15 and F-16 fighters from Denmark and Belgium sent to the Baltics last month. Britain has also offered to send jets, warships and military specialists to support NATO’s eastern flank.

NATO allies have said so far they would not send troops to Ukraine in the event of an invasion. Though the center of the dispute between the West and Russia, Ukraine is not a member and not covered by the alliance’s collective defense clause.

What about Ukraine? Ukraine’s political leadership has largely downplayed the risk of conflict, with Zelensky telling everyone to “take a breath” and “calm down.”

But some Ukrainian commanders have offered a more forceful reaction. Zelensky also signed into law in February plans to strengthen the country’s armed forces, bringing them up from 250,0000 active forces to around 361,000 personnel — though even that is only a third or so of Russia’s 900,000-strong armed forces.

On Sunday, Ukraine’s former defense minister, Andriy Zagorodnyuk, called the situation “pretty dire.” He predicted that Russia had amassed enough troops to occupy Kyiv or another city, but not enough to seize the entire country.

All sides say they are willing to talk. Last week, Turkish President Recep Tayyip Erdogan offered to mediate talks between Ukraine and Russia. Erdogan offer was greeted warmly by Zelensky. who was hosting the Turkish leader in Kyiv.

Turkey is a member of NATO but has maintained relations with Russia — even, controversially, buying missile defense systems.

One potential concession from the United States: Officials confirmed last week that they offered to allow Russia to inspect missile defense systems in Romania and Poland to verify there are no Tomahawk cruise missiles at those sites. In return, the United States would seek inspections of similar sights in the United States.

The United States has long maintained that no Tomahawk missiles are housed in Europe, despite Russian claims.

Sanctions? Western nations have warned of retaliatory actions against Russia if aggression continues, potentially even targeting Russian President Vladimir Putin himself.

Energy? Russia is a major supplier of natural gas to Europe, raising significant questions about what would happen if a conflict led Moscow to cut off the supply. Bloomberg News reported that the Biden administration was seeking alternatives for such a scenario, reaching out to unlikely sources including South Korea and even its other rival, China.