Dozens of injuries were reported in Kyiv and other Ukrainian cities.
Russia has continued a nearly 19-month-long invasion of neighboring Ukraine. Recently, though, the Ukrainians have gone on a counteroffensive, fighting to reclaim occupied territory.
For previous coverage, please click here.
Andrey Vorobyov, the governor of the Moscow region, has suspended mass events outdoors and at educational institutions until July 1.
Moscow Mayor Sergey Sobyanin urged residents to refrain from traveling around the city. Monday was also declared a non-working day for the city. Sobyanin said that a counter-terrorism regime was declared in Moscow and that the situation was difficult.
-ABC News' Tomek Rolski
President Joe Biden spoke with French President Emmanuel Macron, German Chancellor Olaf Scholz and U.K. Prime Minister Rishi Sunak about the developments in Russia.
Biden and Vice President Kamala Harris were also briefed by their national security team on the developments in Russia and will continue to receive updates throughout the day, the White House said Saturday.
-ABC News' Justin Gomez
The governor of the Lipetsk region, which is about 300 miles south of Moscow, said a column of Wagner troops has been spotted in the region, Russian state media reports.
A NATO representative said the alliance was watching what was happening in Russia on Saturday.
"We are monitoring the situation," spokesperson Oana Lungescu said.
-ABC News' Rashid Haddou
