At makeshift checkpoints, motley crews of citizens vow to do everything in their power to halt the Russian advance

• Russia/Ukraine latest

The barricade started as a few men waiting nervously in the road on Friday, and grew gradually over the course of Saturday. By the afternoon, this modest attempt to stop a Russian advance on the capital of Ukraine was complete: sandbags, wooden crates and bricks piled high, with a blue-yellow national flag flying above them.

The motley crew had no illusions about the level of resistance they would be able to offer to one of the world’s most ruthless and technologically advanced armies, but like thousands in and around Kyiv they were determined to do what they could anyway. “I practised shooting yesterday and I came out here today for my first shift. I’ll be honest, I’m terrified,” said Alexander, 50. He was brandishing a US-made Remington shotgun he said a friend had acquired for him.

Analysis: Ukraine’s president has won over critics with his courage and resilience as his country fights for survival

• Ukraine invasion: latest updates

He looked gaunt and unshaven after another sleepless night under Russian attack and bombardment. But Ukraine’s president, Volodymyr Zelenskiy, struck a defiant tone in a video address on Saturday morning. “I’m here,” he said simply. And he was – in the centre of Kyiv, three days on from Vladimir Putin’s invasion, unbowed and going nowhere.

“Good morning everybody! Ukrainians: there’s a lot of fake information online that I call on our army to lay down arms, and that there’s an evacuation,” he said. “I’m here. We won’t lay down our arms. We will defend our state, our territory, our Ukraine, our children. That’s all I have to say. Glory to Ukraine!”

Bombing intensifies as Volodymyr Zelenskiy warns ‘This night will be the hardest’

• Ukraine invasion: latest updates
• Day two: what we know so far

Russian forces have tightened their stranglehold on the Ukrainian capital Kyiv and carried out amphibious assaults on the country’s Sea of Azov coast in an attempt to topple the government.

Almost exactly 30 years after the devastating siege of Sarajevo, another major European capital came under heavy bombardment with shells hitting apartment blocks, driving up the civilian death toll. The onslaught of bombing intensified on Friday night, accompanied by artillery rounds and heavy gunfire on the city’s streets.

Ukrainians prepared a last-ditch defence of their capital, with barricades, and called for civilians to arm themselves with molotov cocktails.

According to US estimates, Russia has fired 200 ballistic and cruise missiles at Ukraine, mostly hitting military targets but some landing in residential areas.

As human rights groups accused Russia of war crimes, the prosecutor at the International Criminal Court issued a reminder he has jurisdiction to investigate atrocities committed inside Ukraine.