The number of refugees fleeing Ukraine has reached 2 million, the head of the UN refugee agency (UNHCR) Filippo Grandi said on Tuesday.

It represents the fastest-growing refugee crisis in Europe since World War II. 

Grandi added that a second wave of refugees from Ukraine is likely to be more vulnerable than the first wave.

"If the war continues we will start seeing people that have no resources and no connections," he said at a press conference in Oslo.

"That will be a more complex situation to manage for European countries going forward," adding that "even more solidarity" will be needed in Europe and beyond.

On Tuesday, Ukrainian officials confirmed that the first safe corridor allowing the evacuation of civilians out of Sumy, northwest of Kharkiv, had been opened. The Russian Defense Ministry had announced routes out of a total of five cities.

Where are refugees going?

Approximately 1.2 million refugees from Ukraine have fled to Poland, including 141,500 on Monday alone, the Polish Border Guard said on Tuesday.

Other neighboring countries have also welcomed a large number of refugees following the war. Hungary has taken in 191,348 and Slovakia 140,745, while Russia took in 99,300 and other European countries have accepted 210,239, according to the latest UN data.

Japan has announced plans to take in refugees from Ukraine and has so far let eight people into the country, the government in Tokyo said Tuesday.

Ukraine refugees will need long-term humanitarian aid

The International Rescue Committee (IRC) told DW that the fallout of the war in Ukraine will need long-term humanitarian solutions to support the high influx of refugees.

"Even if the [war] were to stop right now, there would be a huge amount of humanitarian need inside Ukraine which would make people want to leave to find safety," Nancy Dent, senior global communications officer for the IRC, told DW.

"It’s not a situation that’s going to get fixed anytime soon."

She added: "We need people to be guaranteed access to jobs, able to rent houses, to make sure they can really stand on their own two feet again."

Beyond physical support, "the trauma support that they're going to need is also huge," Dent said.

fh/rt (Reuters, AFP)