Russian President Vladimir Putin dramatically escalated East-West tensions by ordering Russian nuclear forces put on high alert, while Ukraine's embattled leader agreed to talks with Moscow as Putin's troops and tanks drove deeper into the country, closing in around the capital.
Citing "aggressive statements" by Nato and tough financial sanctions, Putin issued a directive to increase the readiness of Russia's nuclear weapons, raising fears that the invasion of Ukraine could boil over into nuclear war, whether by design or mistake.
The Russian leader is "potentially putting in play forces that, if there's a miscalculation, could make things much, much more dangerous," said a senior United States defence official.
Amid the mounting tensions, Western nations said they would buy and deliver weapons for Ukraine, including Stinger missiles for shooting down helicopters and other aircraft, and Ukrainian President Volodymyr Zelenskiyy's office announced plans for a meeting with a Russian delegation at an unspecified location on the Belarusian border.
It wasn't immediately clear when the meeting would take place, nor what the Kremlin was ultimately seeking, either in those potential talks on the border or, more broadly, in its war in Ukraine.
The fast-moving developments came as scattered fighting was reported in Kyiv. Battles also broke out in Ukraine's second-largest city, Kharkiv, and strategic ports in the country's south came under assault from Russian forces. Russian forces had taken Berdyansk, a Ukrainian city of 100,000 on the Azov Sea coast, according to Oleksiy Arestovich, an adviser to Zelenskiyy's office. Across the country, Ukrainian defenders were putting up stiff resistance that appeared to slow Russia's advance.
In the southern port city of Mariupol, where Ukrainians were trying to fend off attack, a medical team at a city hospital desperately tried to revive a 6-year-old girl who was mortally wounded in Russian shelling.
During the rescue attempt, a doctor in blue medical scrubs, pumping oxygen into the girl, looked directly into an AP video camera capturing the scene. "Show this to Putin," he said angrily. "The eyes of this child, and crying doctors."
Their resuscitation efforts failed, and the girl lay dead on a gurney, her jacket spattered with blood.
Nearly 900km away, Faina Bystritska was under threat in the city of Chernihiv.
"I wish I had never lived to see this," said Bystritska, an 87-year-old Jewish survivor of World War II. She said sirens blared almost constantly in the city, about 150km from Kyiv.
Chernihiv residents have been told not to switch on any lights "so we don't draw their attention," said Bystritska, who has been living in a hallway, away from any windows, so she could better protect herself.
"The window glass constantly shakes, and there is this constant thundering noise," she said.
The top official in the European Union outlined plans to buy weapons for Ukraine. "For the first time ever, the European Union will finance the purchase and delivery of weapons and other equipment to a country that is under attack," said European Commission President Ursula von der Leyen. The United States also stepped up the flow of weapons to Ukraine, announcing it will send Stinger missiles, as part of a package approved by the White House on Saturday. Germany likewise plans to send 500 Stingers and other military supplies.
Putin, in ordering the nuclear alert, cited not only statements by Nato members but the hard-hitting financial sanctions imposed by the West against Russia, including Putin himself.
"Western countries aren't only taking unfriendly actions against our country in the economic sphere, but top officials from leading Nato members made aggressive statements regarding our country," Putin said.
US defence officials would not disclose their current nuclear alert level except to say that the military is prepared at all times to defend its homeland and allies. White House press secretary Jen Psaki told ABC that Putin is resorting to the pattern he used in the weeks before the invasion, "which is to manufacture threats that don't exist in order to justify further aggression".
The practical meaning of Putin's order was not immediately clear. Russia and the US typically have land- and submarine-based nuclear forces that are on alert and prepared for combat at all times, but nuclear-capable bombers and other aircraft are not. If Putin is arming or otherwise raising the nuclear combat readiness of his bombers, or if he is ordering more ballistic missile submarines to sea, then the US might feel compelled to respond in kind, said Hans Kristensen, a nuclear analyst at the Federation of American Scientists.