The number of people fleeing Ukraine since Russia launched a war on its neighbor nearly a week ago is "extremely worrying," as some 677,000 refugees have fled the country so far, the head of the UN Refugee Agency said Tuesday in Geneva.

Filippo Grandi, the UN high commissioner for refugees, and Martin Griffiths, the head of the UN's Humanitarian Affairs and Emergency Relief Agency, spoke ahead of a flash appeal for $1.7 billion over three months for soaring humanitarian needs following the start of the Russian-Ukraine War.

"The escalation of conflict has triggered an immediate and steep rise in humanitarian needs as essential supplies and services are disrupted, and civilians flee the fighting," said the UN.

The UN estimates that 12 million people inside Ukraine will need relief and protection, while more than 4 million Ukrainian refugees may need protection and assistance in neighboring countries in the coming months.

Turning to refugees, Grandi said, "The latest figure I just got is 677,000," adding that it had risen by "another 150,000" in less than 24 hours.

He said UN officials had observed lines of vehicles dozens of kilometers long with "people waiting several days" sometimes to cross into neighboring countries.

He said that the UN does have limited mobility inside Ukraine to monitor appropriately.

"But it is likely that if the military offensive continues and urban centers are hit one after the other, that we will see more and more people with less resources, with less connections, more vulnerable in every respect; and that is really what worries us."

About half of the refugees in Poland

Grandi said it is estimated that about half of the refugees have gone to neighboring Poland, and some 100,000 to Hungary, almost 60,000 to Moldova, nearly 50,000 to Slovakia, and some 40,000 to Romania.

The refugee agency also spoke out on reports that have emerged on discrimination against non-Ukrainian or non-European refugees at some entry points.

He quoted the UN secretary-general saying that "there should be absolutely no discrimination between Ukrainians and non-Ukrainians, Europeans and non-Europeans," as all are at risk.

Griffiths said: "The flash appeal for response inside Ukraine will need $1.1 billion in funding for three months to help 6 million of the most vulnerable in the country.” He said that of the 6 million people, "we calculate over a million will be internally displaced."

The UN official said: "We see families with small children, hunkering down in basements and subway stations; we see people running for their lives, to the sound of explosions and wailing sirens."

The flash appeal program includes multipurpose cash assistance for the most vulnerable people, food assistance, water and sanitation, support to health care and education services, and shelter assistance to rebuild damaged homes.

The plan also aims to support authorities in maintaining and establishing transit and reception centers for displaced people and preventing gender-based violence.