A series of powerful explosions rocked residential districts of Kyiv early on Tuesday killing two persons, just hours before talks between Ukraine and Russia were set to resume.
The airport in the eastern city of Dnipro also came under heavy bombardment overnight, as the leaders of Poland, the Czech Republic and Slovenia travelled to the besieged capital Kyiv in a sign of EU support for Ukraine.
Nearly three weeks into Russia's invasion of its pro-Western neighbour, the human toll of the deadly conflict was increasingly laid bare, with more than three million forced to flee to neighbouring countries.
The United Nations said on Tuesday that nearly 1.4 million children have fled Ukraine since the conflict began on February 24 — nearly one child per second.
Ukraine's capital has been transformed into a war zone, with apartment blocks badly damaged from Russian bombardments and half of the city's 3.5 million people now gone.
The city's Mayor Vitali Klitschko said on Tuesday a 35-hour curfew would come into effect from 8:00 p.m. on Tuesday after overnight attacks in the capital.
"Today is a difficult and dangerous moment," Mr. Klitschko said.
"This is why I ask all Kyivites to get prepared to stay at home for two days, or if the sirens go off, in the shelters."
Four large blasts were heard from the centre of the capital early Tuesday, sending columns of smoke high into the sky.
As dawn broke the damage became clear, with one strike hitting a large 16-storey housing block.
There, a fire raged and smoke billowed from the charred husk of the building, as emergency services and stunned locals navigated an obstacle course of glass, metal and other debris littering the road.
Another residential building in the Podilsk area also came under attack.
"At 4:20 everything was very thunderous, crackling. I got up, my daughter ran to me with a question: 'Are you alive?'," Lyubov Gura, 73, told AFP minutes after rescuers let her and her daughter out of her 11th-floor apartment.
She was still waiting for emergency workers to lower her son-in-law and grandson to the ground.
The district was once "a place to get coffee and enjoy life. Not anymore," Ukrainian MP Lesia Vasylenko said.
The city is surrounded to the north and east, and authorities have set up checkpoints, while residents are stockpiling food and medicine.
Overnight shelling also caused massive damage at the airport in the eastern Ukrainian city of Dnipro, regional authorities said Tuesday.
"During the night the enemy attacked the Dnipro airport. Two strikes. The runway was destroyed. The terminal is damaged. Massive destruction," region governor Valentin Reznichenko said.
Hours earlier, Ukrainian President Volodymyr Zelensky issued a new video address sounding a note of cautious optimism about ongoing peace talks.
He claimed Russia was realising victory would not come on the battlefield.
"They have already begun to understand that they will not achieve anything by war," Mr. Zelensky said.
He said Monday's talks were "pretty good... but let's see. They will continue" on Tuesday.
The two sides are still far apart in the negotiations, with Moscow demanding Ukraine turn away from the West and recognise Moscow-backed breakaway regions.
Ukrainian negotiators say they want "peace, an immediate ceasefire and the withdrawal of Russian troops".
In an unprecedented show of solidarity with the embattled president, the Polish, Czech and Slovenian Prime Ministers boarded a train for Kyiv to meet Zelensky on Tuesday.
"In such crucial times for the world, it is our duty to be in the place where history is being made," Poland's Mateusz Morawiecki said in a Facebook post.
It is the highest-level EU delegation to go to Kyiv since the war began.
Russia's military progress has been slow and costly, with Moscow apparently underestimating the strength of Ukrainian resistance.
Military experts believe Russia's military now needs time to regroup and resupply its troops, paving the way for a possible pause or slowdown in fighting.
The head of Russia's national guard Viktor Zolotov has reportedly admitted the operation was "not going as fast as we would like" but said victory would come step-by-step.
Reports say Moscow has turned to Beijing for military and economic help — prompting what one U.S. official said were several hours of "very candid" talks between high-ranking US and Chinese officials.
On Tuesday, Chinese Foreign Minister Wang Yi said his nation does not want to be impacted by Western sanctions on Russia, as US pressure grows on Beijing to withdraw support from Moscow.
"China is not a party to the crisis, still less wants to be affected by the sanctions," Mr. Wang said.
Russian President Vladimir Putin has ordered his forces "to hold back on any immediate assault on large cities" according to Kremlin spokesman Dmitry Peskov Monday, who cited "civilian losses" as the reason for stalling an attack.
He added, however, that the defence ministry "does not rule out" the possibility of putting large cities "under its full control".
