Ukrainian refugees board a train en route to Warsaw at the railway station in Przemysl, near the Polish-Ukrainian border, on March 27, 2022. Photo: AFP

The United Nations warned Tuesday that more than 8 million Ukrainians could flee as refugees in 2022 and doubled its aid appeal for those stuck inside the war-ravaged country.

Nearly 5.3 million Ukrainians have already fled Ukraine since the start of the Russia-Ukraine crisis on February 24, fueling Europe's fastest-growing refugee crisis since World War II.

The UN refugee agency, which initially forecast that up to 4 million people would flee in 2021, said it would need $1.85 billion to support refugees in neighboring countries.

UNHCR spokeswoman Shabia Mantoo said it was "anyone's guess as to when we will reach this 8.3-million figure," stressing that "the situation is highly dynamic."

"These displacements are still occurring every day. Every hour we are seeing people continue to flee Ukraine," she told reporters in Geneva.

"This displacement has been on such an expansive scale, and the rapidity of this we haven't seen in recent times." 

After just two months of war, the Ukraine conflict appears set to soon produce more refugees than Syria, which after 11 years of civil conflict saw 6.8 million of its nationals register as refugees.

The demographics of Ukraine's refugee population also differ from many other crises.

Women and children account for 90 percent of those who have fled abroad, with men aged 18 to 60 eligible for military call-up unable to leave.

The UNHCR said that neighboring host countries had the capacity to respond to the crisis, but that "the scale of refugee arrivals and the breadth of their needs requires further support for national social protection systems and services."

Nearly six out of 10 Ukrainian refugees - more than 2.9 million - have fled to Poland. 

While the rapidly rising refugee numbers are staggering, they do not paint the full picture.

Around 7.7 million people have been displaced from their homes but remain inside Ukraine, meaning that 12.7 million total have been uprooted since the crisis began.

"Almost 13 million more people are also estimated to be stranded in affected areas or unable to leave due to security risks," Mantoo said. 

The UN humanitarian agency OCHA estimated Tuesday that 15.7 million people in Ukraine are in need of humanitarian aid, up from its previous estimate of 12 million.

Before the conflict, Ukraine had a population of 37 million in the regions under government control.

AFP