Ukraine’s leader, who was already in turmoil, agreed to talks with Moscow while Putin’s troops drove deeper into Ukraine.

Putin issued a directive to Russia to increase its nuclear weapons readiness, citing NATO’s “aggressive remarks”. This step raised concerns that an invasion of Ukraine could escalate into nuclear war.

A senior U.S. defense official said that the Russian leader could “potentially put in play forces, which, if there is a miscalculation of it, could make it much, more dangerous.”

In the midst of increasing tensions, the Ukrainian President Volodymyr Zelenskyy announced that the two countries would meet at an unspecified place on the Belarusian border. Sunday was a waiting day for a Russian delegation.

The Kremlin’s final goals in Ukraine, and the steps that might suffice to satisfy Moscow, remain unclear.

These rapid-moving developments occurred as scattered fighting was reported from Kyiv, battles brokeout in Kharkiv (the second-largest Ukrainian city), and Russian forces attacked strategic ports in the country’s south.

The Russian troops were closing in on Kyiv, a city with almost 3 million inhabitants, and the mayor of the capital expressed concern that civilians might not be evacuated.

Ukraine’s defenders faced stiff resistance across the country that seemed to slow down Russia’s advance.

A medical team from Mariupol tried desperately to save a 6-year old girl who had been mortally injured by Russian shelling in her southern port city.

During the rescue attempt, a doctor wearing blue medical scrubs pumped oxygen into the girl and looked directly into the Associated Press video camera that captured the scene.

He screamed angrily, “Show it to Putin.” “The eyes of this baby, and the crying doctors.”

The girl was found unconscious on a gurney and her jacket was covered in blood.

Faina Bystritska, who was located nearly 900 km (560 miles) from Chernihiv, was under threat.

Bystritska (87 years old) said, “I wish that I hadn’t lived to see it.” She is a Jewish Holocaust survivor. She claimed that sirens are heard almost continuously in the city, which is located about 150 km (90 miles) away from Kyiv.

Chernihiv residents were told not to turn on any lights, “so they don’t attract their attention,” stated Bystritska. She has been living in a hallway away from windows to protect herself.

She said, “The window glass shakes constantly and there is a constant thundering sound.”

The top European Union official outlined plans for the bloc of 27 nations to shut down its airspace to Russian airlines, and to purchase weapons for Ukraine.

Ursula von der Leyen, President of the European Commission, stated that “for the first time ever”, the European Union will fund the purchase and delivery weapons and other equipment to a nation under attack. She also stated that the EU would ban certain pro-Kremlin media outlets.

In a package that was approved Friday by the White House, the U.S. announced it would send Stinger missiles to Ukraine. These can be used to shoot down helicopters. Germany also plans to send 500 Stingers as well as other military supplies.

The emergency session of the 193-member U.N. General Assembly on Monday was also scheduled. It will focus on Russia’s invasion.

Putin ordered the nuclear alert citing not only statements made by NATO members, but also the severe financial sanctions imposed on Russia by the West, which included Putin.

Putin made the remarks in televised comments, “Western countries don’t just take unfriendly actions against our nation in the economic realm but also top officials of leading NATO members made aggressive statements about our country.”

U.S. defense officials wouldn’t disclose the current level of nuclear alert, except to state that the military is always ready to defend its homeland as well as allies.

Jen Psaki, White House Press Secretary, stated to ABC that Putin is using the same strategy he used weeks before the invasion: “To make threats that don’t exist to justify further aggression.”

Putin’s order did not have a clear practical meaning. Russia and the United States have typically both submarine- and land-based nuclear forces, which are always on alert and ready for combat. However, nuclear-capable bombers are not.

Hans Kristensen, a nuclear analyst with the Federation of American Scientists, stated that if Putin is increasing the nuclear combat readiness of its bombers or ordering more ballistic missile submarines to sea, the U.S. may feel obliged to do so.

After the explosions that lit up the sky on Sunday morning, Kyiv was quiet. Authorities also reported reports of blasts at one airport. Because of the strict curfew, the main boulevard was virtually deserted. Officials warned that anyone attempting to leave without a pass would face being considered a Russian spy.

In fear of a Russian invasion, terrified residents took refuge in underground garages, subway stations and homes. Vitali Klitschko, Kyiv Mayor, stated that food and medicine were low.

Authorities have been giving weapons to anyone who wants to defend the city. Ukraine also releases military veterans who are willing to fight and trains people to make firebombs.

Klitschko stated, “Right now the most important question it to defend our country.”

Olena Dudnik, an 86-year old woman from Kharkiv, said that she was almost thrown out of her bed by the blast of a nearby pressure explosion.

Dudnik, a Ukrainian fighter, said that there were street fights every day, even in downtown. They are trying to stop Russian tanks and armored vehicles, as well as missile launchers. According to her, the lines at drugstores can be hours long.

She said, “We are suffering tremendously.” “We don’t have enough food in our pantry and I worry that the stores won’t have any if they reopen.”

According to Pentagon officials, Russian troops are being slowened by fuel shortages, resistance from Ukraine, and other logistical issues. However, Ukraine’s air defense systems are still operational, despite being weaken.

However, a top U.S. defense official stated that this will likely change: “We’re in day four.” Russians will adapt and learn.”

Putin has not yet revealed his final plans. However, Western officials believe that he intends to overthrow the Ukrainian government and install his own regime, which would bring back Moscow’s Cold War-era influence.

In the fog of war, it was not clear how many people were killed in Europe’s largest land conflict since World War II.

The health minister of Ukraine reported that 198 people had been killed, with three children among them, and that more than 1,000 were wounded. It wasn’t clear if those numbers included civilian and military casualties.

Maj. Gen. Igor Konashenkov, Russian Defense Ministry spokesperson, did not give any figures on Russia’s deaths and injuries but stated that Russia’s losses were “many-times” less than those of Ukraine.

According to U.N. refugee agency, 368,000 Ukrainians have arrived at neighboring countries since Thursday’s invasion.

The U.S., European Union, and Britain also agreed not to provide military assistance. However, they did agree to block selected Russian bank from SWIFT. This system moves money around thousands more financial institutions and banks worldwide. They also decided to place restrictions on Russia’s central banks.

Russia’s economy has been suffering since the invasion. The ruble is down and the central bank calls for calm in order to avoid bank run.

Russia, which has nearly 200,000 troops positioned along Ukraine’s border, claims that its assault is only aimed at military targets but also bridges, schools, and residential areas have been struck.