With Russian troops on the offensive, Ukraine's second-largest city is taking the drastic step of moving classrooms for primary and secondary education underground.
Russia is still reeling from Friday's attack. Authorities have confirmed at least 137 dead. Suspects, some showing signs of torture, have been charged. Here are other key developments.
Reports from Moscow say two to five gunmen attacked a concert hall outside the capital. A fire broke out after the attack. According to Tass news agency, some people remain trapped in the building.
The Ukrainian energy minister said the nighttime drone and rocket attacks were "the largest attack on the Ukrainian energy sector in recent times." At least three people were killed, officials said.
Vladimir Putin won a landslide reelection victory, taking some 87% of all ballots following three days of voting derided by Russia's opposition and the West as neither free nor fair.
Russian President Vladimir Putin will extend nearly a quarter century of rule for six more years after wrapping up an election that gave voters no real alternatives.
Putin forever? Russia's president goes into this week's election with no serious contenders, cementing his already quarter-century hold on the Kremlin through at least 2030.
Sweden has formally joined NATO as the 32nd member of the transatlantic military alliance, ending decades of post-World War II neutrality as concerns about Russian aggression in Europe have spiked.