And the authorities are calling on the rest of Europe and the UK to "invite" those arriving in Poland who've fled from war.

Monika Beuth-Lutyk, spokesperson for the mayor of Warsaw, told Sky News: "I think we should all do more. The real problem is before us."

Ukraine-Russia live updates: Russia says it will open humanitarian corridors every day - as 47 people are buried in a mass grave

Asked whether Britain should be doing more, she said: "I am afraid that this is just the beginning - so I think you could today think about your offer for them if you can provide something for them that would be really welcome."

Around a million and a half refugees have crossed the border into Poland - and around 300,000 have arrived in Warsaw. That's about 15% of the existing population.

At the city's Central Station there were thousands - either arriving off trains from Ukraine; receiving aid; sleeping rough or trying to work out what to do next.

Nobody knows how many people intend to stay in Poland or move on to other countries.

It's a moment to re-group and receive basic hand outs like a toothbrush, medicine and food and water.

But asking one woman where she plans to go next she said simply: "I have no idea."

It's all still a terrible shock that they're even here. Gregory fled from the eastern Ukranian city of Kharkiv with his 87-year-old mother Lillie. He told us she feels ashamed to be in this position and also still - in spite of reaching Poland - afraid of the Russians.

He said: "We have no home, we have no cars, we have no nothing. Only these three baggage. That's all."

Ykaterina Zakharchenko, her mother and daughter lived near the Zaporizhzhia nuclear power plant in Ukraine.

Russia's invasion of Ukraine mapped - what happened on day 15

She told us they want to get as far away from the nuclear plant as possible - ideally to the UK but as they don't have any relatives there, they aren't eligible for the visa scheme.

They stress how kind they believe the Poles are being towards the fleeing refugees.

But, seeing the pressure the authorities in Warsaw are under, they don't plan to stay here.

'We don't want to bother Polish people'

Ms Zakharchenko, a lighting technician at a circus, says: "We are going to Germany because there are too many of our citizens in Poland and we don't want to bother Polish people."

Her mother Irina Zakharchenko told us: "They all try to help, to feed, to sleep and take care of our children."

Polish volunteer, Anna Blachowska, is helping hand out coffee and food.

She said: "There are a lot of people here and it is not that planned and organised. We are trying to do it ourselves but it is not that easy.

"I don't know how long it is going to be but probably for a long time. It is not just a moment, we have to be prepared it is going to be a few months."

There are lines of people sleeping rough - waiting for trains that are too full to take them.

And volunteers do what they can to entertain the enormous number of children evacuated with their mothers. We see a young boy's face light up as he's given chocolate. Not old enough to truly understand why strangers are being so kind.

Follow the Daily podcast on Apple Podcasts, Google Podcasts, Spotify, Spreaker

A teenager we meet aged 17 is old enough to know what's going on - but not old enough to fight. He says he only plans to stay until his 18th birthday when he can return to his homeland and join the war effort.

Standing with a friend, they're counting money freshly acquired from an exchange bureau.

A volunteer dashes past having helped a woman who can't speak Polish change her money. She's in a hurry as the woman she's helping wants to get a train.

There is immense goodwill everywhere. But it's coming under immense strain and it's only two weeks since Russia invaded Ukraine with little sign of peace in sight.