The top floor of an office building in central Kyiv has been transformed into a makeshift military supply depot as ordinary Ukrainians took up arms to defend their city from Russian invaders.

By Saturday, three days into Russia's assault on Ukraine, armed men in military fatigues with yellow masking tape around their sleeves were helping the troops defending Kyiv. The city centre is believed to have Russian agents in it.

Automatic weapons were propped up against the walls of the abandoned office block and there were boxes with drones destined for frontline troops on the floor.

In an adjoining room, young volunteers were busy writing posts for the operativno channel on the social media platform Telegram, telling Ukrainians about the progress of the war and how to help their country. The kitchen had bottled water and stock of last-minute food supplies as most of the grocery stores in the city closed.

Donations of money, clothes, food, power banks and weaponry have been made by the Ukrainian diaspora and civilians in response to the Russian president's order to invade.

In a country with a long history of partisan warfare, Ukrainians say they expect civilians to engage the Russians in a fierce battle if troops advance toward the city centre.

Serhiy Prytula, a television celebrity turned politician who joined the democratic uprising in Ukraine and this week put on a uniform, said that Kyiv is not a simple place where the Russians can just walk around.

Armed volunteers at a depot for Ukraine’s territorial defence forces
Volunteers at a depot for Ukraine’s territorial defence forces in Kyiv on Saturday © Erin Trieb/Bloomberg

After a weapons distribution scheme was announced this week, about 18,000 people picked up guns in Kyiv alone.

President Volodymyr Zelensky, who some Ukrainians once dismissed as a frivolous figure, has stepped into a role similar to that of a British Prime Minister after Russia's invasion of Ukraine.

Since the invasion, his office has regularly published what are essentially proof of life videos filmed in the government complex, featuring messages from the Ukrainian leader who says Russia wants to assassinate him.

The goal of securing a quick victory has been defeated in several places.

A damaged vehicle after Russian missile strikes in Kyiv
A damaged vehicle after Russian missile strikes in Kyiv on Saturday © Bloomberg

Young people have been gathering in bars, restaurants, and other places around the city to make Molotov cocktails, because of the halt in Russian heavy vehicles.

The internal affairs ministry published a how-to information graphic on Telegram this week, after the military urged people to make their own weapons. The ministry encouraged people to use them in Obolon, the suburb where Russian troops have halted their advance.

Oleksandr, who ran a clothing company before the war began, has been using petrol and jam jars.

He told the Financial Times that it was easy to destroy a tank by throwing just one or two at the back. You can put a Molotov in the place where the crew is sitting.

Oleksandr joined weekend training sessions organised by the Azov Battalion and learned how to make petrol bombs.

Some of the civilian fighters in eastern Ukraine gained combat experience during the hybrid invasion of the Donbas region by Russia.

Roman Sinicyn, a former businessman and political activist who volunteered as a fighter in the Donbas in 2014, said that this is their land and they don't have any choice.

He said that he was going to help the guys have more supplies and that he would kill Russians if he saw them.

Masi Nayyem, a lawyer and war veteran, said that years of conflict first in eastern Ukraine and now the nationwide war with Russia meant that nobody is afraid.

As a child, Nayyem migrated to the Soviet Union from Afghanistan. He said that he was from Ukraine.

He is confused by the west's failure to stop Putin.