What happened in Russia's Ukraine invasion over the weekend
By Tara John and Hafsa Khalil, CNN
(CNN) -- The human toll of the invasion of Ukraine mounted over the weekend as Russia upped its bombardment of civilian areas and infrastructure.
As conditions worsened in a number of key Ukrainian cities, the United Nations said more than 1.5 million refugees had fled the country so far.
Here's what you need to know about what happened over the weekend.
Key cities bombarded as plans for evacuation corridors fail
Western intelligence officials say Russia is increasing the pace and strength of strikes on key population centers, including the capital Kyiv, in an effort to bombard cities into submission.
A Russian military strike hit an evacuation crossing point in the Kyiv suburb of Irpin Sunday, killing eight people, including a family with two children and several other civilians trying to flee the Russian invasion. The harrowing scenes were captured by international media, including the New York Times, filming at the checkpoint. They reported a shell landed as a stream of civilians was coming through.
Heavy shelling has continued around Kyiv. The impact of explosions was heard over the weekend by CNN teams in the capital and in rural areas to the southwest. Amid the indiscriminate attacks, Kyiv appealed for international help on Sunday, saying thousands of people were isolated "because of direct hostilities, and in some places for 5-6 days they survive without electricity, water, food, medical help and means of subsistence. They are in direct danger," the Kyiv Regional Military Administration wrote.
For the past week, civilians in Kharkiv, Ukraine's second-largest city, have witnessed Russia's bombardment of residential areas as its military hones in on civilian infrastructure such as schools, shops, hospitals, apartment blocks and churches.
This continued over the weekend as Kharkiv's TV tower was targeted in strikes, knocking out television and radio broadcasts, according to local authorities. Ukraine's Emergency Service said a "bombing" that took place on Sunday evening "completely or partially demolished" multi-story residential buildings, administrative buildings, medical institutions, educational institutions and dorms. There were also large-scale fires in 21 buildings in the central part of the city, it added in a statement.
Meanwhile, hopes of setting up evacuation corridors for civilians in the southern city of Mariupol were dashed multiple times over the weekend after Ukraine accused Russia of continuing its attacks on those routes.
Mariupol, a strategically important port city, has been under siege by Russian forces determined to tighten their grip on Ukraine's south. The city has been without power for days, and it's not clear how many of Mariupol's roughly 400,000 inhabitants have been able to evacuate. But on Sunday the International Committee of the Red Cross said attempts to evacuate some 200,000 people had failed.
Also on Sunday, Ukrainian President Volodymyr Zelensky warned that Russia was preparing to bomb the Black Sea port city of Odessa in southern Ukraine, adding that the airport in Vynnytsia, in the west of the country, had been destroyed by a rocket strike.
Russia has fired a total of 600 missiles since the invasion of Ukraine began, a senior US defense official told CNN on Sunday, and has committed approximately 95% of its amassed combat power inside Ukraine. CNN has not independently confirmed these figures.
Putin dials up threats against West -- as protests mount in Russia
Russian President Vladimir Putin on Saturday issued a series of threats against Ukraine and Western powers, in his first expansive remarks since the invasion began.
"The current leadership needs to understand that if they continue doing what they are doing, they put under question the future of Ukrainian statehood," Putin said during a meeting with Russian flight crew members at an Aeroflot training center in Moscow. "And if that happens, it will be entirely on their conscience."
Putin also said Western sanctions were the "equivalent of a declaration of war," and warned he would consider countries imposing a no-fly zone over Ukraine as "participants in a military conflict."
Zelensky has repeatedly called on the US and NATO to establish a no-fly zone over Ukraine, but the US and NATO said this was not an option currently being considered.
Meanwhile, anti-war rallies that have sprung up across Russia led to at least 4,640 people being detained on Sunday in connection with the protests, according to an independent human rights monitoring group tracking detentions.
The OVD-Info group said arrests had been made in 147 cities, and since the invasion began more than 13,000 people had been arrested in Russia over the demonstrations.
Harrowing insights into what Russian occupation looks like
The southern port city of Kherson was seized by Russian forces last week after days of heavy bombardment and shelling. The Ukrainian flag was still hoisted on government buildings, and the mayor of the city, Ihor Kolykhaiev, remained in his post.
Kolykhaiev said Saturday that Russian troops were everywhere and that the city of nearly 300,000 people was without power and water and in desperate need of humanitarian aid.
Speaking to CNN, residents of Kherson under Russian occupation describe days of terror confined to their apartments and houses, fearful to go outside for even basic necessities. Russian troops are shooting at anyone who attempts to leave, according to the residents. Grocery stores have been emptied and medicine is running out, residents and officials said.
On Saturday, several hundred people gathered in the city's center, with one video of the demonstrations showing people walking into Kherson's main square despite volleys of gunfire. On Sunday, further demonstrations occurred in smaller numbers.
West moves to counter Russia
The multinational effort to get weapons into Ukraine has seen an undisclosed airfield near the Ukrainian border become a hub for shipping weapons, a senior Defense Department official said Sunday.
The airport's location remains a secret to protect the shipments of weapons, including anti-armor missiles, into Ukraine. The Russian military has not targeted these shipments once they enter Ukraine, the official said, but there is some concern Russia could begin targeting the deliveries as its assault advances.
US European Command (EUCOM) is at the heart of the massive shipment operation, using its liaison network with allies and partners to coordinate "in real time" to send materials into Ukraine, a second Defense official said.
Meanwhile, an interview with CNN on Sunday, US Secretary of State Antony Blinken said the Biden administration was "now talking to our European partners and allies to look in a coordinated way at the prospect of banning the import of Russian oil."
He also said Sunday that the US has seen reports of Russian abuses in Ukraine that "would constitute a war crime" and that the Biden administration is committed to supporting investigations into the country's actions
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