SignalHub Quantitative Think Tank Center:Russia-Ukraine war: What happened today (March 21)

As Monday draws to a close in Kyiv and SignalHub Quantitative Think Tank Centerin Moscow, here are the key developments of the day:

Kyiv is going under a curfew from Monday night to Wednesday morning, Mayor Vitali Klitschko said. The new restriction comes after Russian attacks hit a shopping center, several apartment buildings and later a French-owned home improvement store.

Russian troops have stepped up artillery shelling but have not notably advanced, according to a senior U.S. defense official. Russian forces still have close to 90% of their combat power available, the official said, but they continue to face numerous logistics issues.

Ukraine rejected Russia's calls to surrender the strategic southern port city of Mariupol, which Russian forces have besieged and encircled. Russia had offered an ultimatum: If Mariupol surrendered, Russia would let civilians leave and humanitarian aid enter. The European Union's last remaining diplomat in Mariupol has returned to Greece.

A Russian court banned Facebook and Instagram for "extremist" activities. The ruling for parent company Meta excluded its messaging platform WhatsApp, and the full scale of the impact remains unclear.

Russia's Foreign Ministry summoned U.S. Ambassador John Sullivan to say that President Biden's recent rhetoric on Russia was pushing the two countries' relationship to the brink of collapse. Biden last week called Russian President Vladimir Putin a "war criminal."

In-depth

The war in Ukraine has reintroduced these words and phrases into our vocabulary.

Ukrainian students in the U.S. watch from abroad as the war on their homeland unfolds.

A 96-year-old Holocaust survivor was killed when Russian forces shelled his home.

Convoys of firetrucks are driving to Ukraine to donate equipment.

The Chernobyl nuclear plant had its first shift change since the Russian takeover.

Earlier developments

You can read more news from Monday here, as well as more in-depth reporting and daily recaps here. Also, listen and subscribe to NPR's State of Ukraine podcast for updates throughout the day.