An estimated 500,000 people have fled Ukraine to the eastern edge of the European Union (E.U.) since Russia invaded Ukraine last Thursday, U.N. High Commissioner of Refugees (UNHCR) Filippo Grandi said on Monday.

“More than 500,000 refugees have now fled from Ukraine into neighbouring countries,” he wrote in a statement shared by Twitter on February 28.

Earlier on February 27, Grandi wrote on Twitter, “The number of refugees from Ukraine who have crossed to Poland, Hungary, Romania, Moldova and other countries is escalating and is now 368,000.”

UNHCR spokeswoman Shabia Mantoo estimated on Monday that of Ukraine’s displaced people, “281,000 [were] in Poland, 84,500 in Hungary, 36,400 in Moldova, 32,500 in Romania and 30,000 in Slovakia.”

“The rest were scattered in unidentified other countries,” she added, as quoted by the Associated Press (AP).

The news agency said it witnessed Ukraine’s mass exodus flooding the borders of “Poland, Hungary, Slovakia, Romania and non-EU member Moldova” on February 28. On Monday, the AP visited a temporary migrant reception center in the Hungarian village of Beregsurany — which borders western Ukraine’s Berehove Raion district — as the center accepted people traveling from Ukraine to the E.U.

“Many of the refugees at the reception center in Beregsurany, as in other border areas in Eastern Europe, are from India, Nigeria and other African countries, and were working or studying in Ukraine when the war broke out,” the news agency revealed.

“Hungary, in a turnaround from its long-standing opposition to immigration and refusal to accept refugees from the Middle East, Africa and Asia, has opened its borders to all refugees fleeing Ukraine, including third-country nationals that can prove Ukrainian residency,” the New York City-based AP observed.

Russia’s military invaded Ukraine on the morning of February 24, prompting many Ukrainians and other people residing in Ukraine to leave the country over the past four days.

“Most of those fleeing Ukraine were entering the EU from its eastern flank, with some traveling on to countries further west,” the AP noted of the mass migration.

A woman named Aksieniia Shtimmerman is one example of a refugee who traveled further into the E.U. beyond Ukraine’s immediate border. Shtimmerman, 41, told the news agency she and her four children traveled for three days from Kyiv, Ukraine’s national capital, before arriving in Berlin, Germany, on Monday.

A spokesman for Germany’s Interior Ministry said on Monday that “1,800 refugees from Ukraine had arrived in Germany so far.”

“The EU is preparing to allow fleeing Ukrainians the right to stay and work in the 27-nation bloc for up to three years,” Deutsche Welle reported on February 28, citing senior E.U. and French government officials.