Russian strikes hit fresh civilian targets in central and eastern Ukraine on Friday, including a city previously considered a safe haven, as Moscow's troops edged closer to the capital Kyiv.
More than two weeks after Russia invaded its neighbour on February 24, hundreds of thousands of civilians remain trapped and under bombardment, while the UN estimates some 2.5 million have fled.
Western powers have imposed unprecedented sanctions on Moscow and sent funds and military aid to Kyiv, but have failed to halt Russia, with overnight strikes again reported across Ukraine on Friday.
The first high-level talks between the two sides on Thursday failed to make a breakthrough although Russian President Vladimir Putin said Friday there were "certain positive shifts."
He added that negotiations are "now being held on an almost daily basis."
Three missiles hit civilian buildings in the central city of Dnipro early Friday, destroying a shoe factory and killing a security guard.
The city had been considered a safe haven, becoming a hub for the coordination of humanitarian aid and those fleeing more severe fighting in the country's east.
"Today, we were supposed to host people who need a lot of support," said Svetlana Kalenecheko, who lives and works in a clinic that was damaged in the attack.
"Now we can't help anyone."
Elsewhere, a care home for disabled people was hit in the village of Oskil, near Kharkiv in eastern Ukraine, in Russian strikes which also destroyed five houses, local officials said.
There were no reports of casualties. At the care home, all 30 staff members and 330 mostly elderly patients — 10 of whom require wheelchairs — had been sheltering at the time.
Military targets were also hit early Friday, with four Ukrainian servicemen killed in strikes on the Lutsk military airport in the northwest, local officials said. Moscow said the airfield had been "put out of action."
Meanwhile the advance of Russian forces continued against the capital Kyiv, which risks being entirely surrounded.
The Ukrainian military warned Russia was trying to "block" Kyiv by taking out defences to the west and north of the capital, adding that there was also a risk to Brovary in the east.
Kyiv's mayor Vitali Klitschko said Thursday that half the city's population had fled and the capital "has been transformed into a fortress."
The northwest suburbs, including Irpin and Bucha, have already endured days of heavy bombardment but Russian armoured vehicles are also advancing on the northeastern edge.
Ukrainian soldiers described fierce fighting for control of the main highway leading into the capital, and AFP reporters saw missile strikes in Velyka Dymerka just outside Kyiv's city limits on Thursday.
Britain's defense ministry said Russian forces were committing increased number of forces to encircle key cities, reducing numbers available to continue the advance.
The Kremlin said Friday that fighters from Syria and the Middle East would be allowed to fight for Russia in what Moscow calls a "special military operation" in Ukraine.
The Russian army this week admitted conscripts were taking part, after Putin previously said only "professional" soldiers were involved.
Ukrainian President Volodymyr Zelenskiy accused Russia of hiring "murderers from Syria, a country where everything has been destroyed... like they are doing here to us."
In a video message recorded outside his presidential office in Kyiv, Zelensky also demanded the European Union "do more" to help his country.
EU leaders meeting in France on Friday were expected to back a proposal to double financing for military aid to Ukraine by an extra 500 million euros ($550 million).
Late Thursday the U.S. congress passed a budget including $14 billion in humanitarian and military aid for Ukraine.
But the U.S. has ruled out enforcing a no-fly zone, and rejected a Polish plan to transfer fighter jets to Ukraine via a US air base for fear of being drawn directly into the conflict.
NATO chief Jens Stoltenberg told AFP Friday the military alliance had "a responsibility to prevent this conflict from escalating beyond Ukraine's borders to becoming a full-fledged war between Russia and NATO."
Desperation in Mariupol
The southern port city of Mariupol has suffered relentless bombardment, and Zelensky said Thursday that attempted aid deliveries had been hit.
He said Moscow had launched a "tank attack" targeting a humanitarian corridor where he had dispatched a convoy to try to get food, water and medicine into the city.
The attack, which Zelenskiy described in a video statement as "outright terror," came a day after the bombing of a children's hospital there that local officials said killed three people, including a young girl.
Zelenskiy branded that attack a "war crime," a position backed by top Western officials, while Russia's army claimed the bombing was a "staged provocation" by Ukraine.
In a video, Mariupol mayor Vadym Boichenko said Russian warplanes had targeted residential areas in the city "every 30 minutes" on Thursday, "killing civilians, the elderly, women and children."
The situation in the city has been described as "apocalyptic," with more than 1,200 civilians killed in days of constant attacks, according to the mayor.
The International Committee of the Red Cross said some residents had started fighting for food, and many had run out of drinking water.
Yulia, a 29-year-old teacher who fled Mariupol, said her mother-in-law was still there, and told them "the attacks don't stop".
"There are many corpses on the street and nobody buries them," she told AFP.
Facebook violent speech
Some humanitarian corridors out of cities under attack have held.
Around 100,000 people have been able to leave the northeastern city of Sumy, the eastern city of Izyum, and areas northwest of Kyiv in the last two days, Ukrainian officials said.
Moscow said it would also open daily humanitarian corridors to evacuate civilians to Russian territory, but Kyiv has rejected routes leading to Russia.
Later Friday, the UN Security Council will hold an emergency meeting at Russia's request, over its claims that the US is funding research into the development of biological weapons in Ukraine.
Both Washington and Kyiv have denied the allegations, with the U.S. saying they were a sign that Moscow could soon use the weapons itself.
Russia meanwhile said it was opening a criminal case against Meta, the U.S. parent company of Facebook and Instagram, for "calling for the murder" of Russians after the firm eased its policy on violent speech.
The UN also voiced alarm at the decision — which would allow statements like "death to Russian invaders" but not credible threats against civilians — saying it could spark hate speech against Russians.