The UN said on Friday that almost half the refugees who fled from Ukraine to neighbouring countries have since moved on to other European nations.
More than 6.6 million people have poured across Ukraine's borders since Russia invaded on February 24, the vast majority of them women and children. About 2.9 million are no longer in the border states where they first arrived, the UN refugee agency said.
Germany, Italy and the Czech Republic are the most common destinations for people moving on to a third country, UNHCR figures show.
Poland is the most-affected border country, followed by Romania, Hungary, Moldova and Slovakia. Some people have ended up in Russia, but Ukraine says these include forced removals.
About 100,000 refugees per day were arriving at the Polish border in early March but the number has slowed to roughly 20,000 throughout May. Polish railways have offered free onward travel for people heading to Germany and other countries.
People's needs are only increasing as the conflict grinds on and strong support from the wider international community will be needed to maintain the initial show of generosity, said UNHCR spokeswoman Olga Sarrado.
“Newly arrived refugees often come from areas heavily affected by the fighting, some having spent weeks hiding in bomb shelters and basements,” Ms Sarrado told a briefing in Geneva, speaking remotely from a refugee centre in Warsaw.
“They often arrive in a state of distress and anxiety, having left family members behind, without a clear plan for where to go and with less economic resources and connections than those who fled earlier.
“Support will need to be provided so they can stay in the country until they can go back and live with dignity.”
In the first weeks of the war, volunteers flocked to help at the borders and at railway stations or welcomed new arrivals into their homes.
More than 1.1 million people have registered with the Polish authorities and received an ID number which gives them access to public services. About 94 per cent of those registered are women and children.
Ukrainians have crossed into Poland more than 2.1 million times since February 28, although these are not necessarily permanent returns.
“We have also seen more pendular movements, where people go back and forth across the border to Ukraine for various reasons, including visiting families, checking their properties or returning to their jobs,” said Ms Sarrado.
“However, Poland expects to continue receiving and hosting a considerable number of refugees, given the large internal displacement, massive destruction and the ongoing hostilities in Ukraine.”
Before the invasion, Ukraine had a population of 37 million in the regions under government control, excluding Russia-annexed Crimea and the pro-Russian separatist-controlled regions in the east.
