GENEVA — Two million refugees have now fled Ukraine since Russia's invasion, said the UN's refugee agency.

More than half have passed over the border into Poland, the latest figures show. Around 100,000 have fled to Russia and 450 to Belarus.

Filippo Grandi, the head of the United Nations High Commissioner for Refugees (UNHCR), said at the weekend the crisis was Europe's fastest-growing refugee crisis since World War II.

In another development, UK Ministry of Defense said that the strength of Ukrainian resistance has surprised Moscow.

Lviv is a town along the Ukrainian-Polish border that has been greatly touched by the war, despite not seeing any fighting.

For thousands of refugees, it is a place to pass through on their way to Poland. And for those left behind, it is a city preparing for battle, as roadblocks reinforce Lviv’s entrances and volunteers learn how to fight.

In one class on guerrilla warfare in the city, an instructor taught a group of 50 people how to load a gun. "There’s a hole here. You put the ammunition in and hold the magazines like this,” he told the novices.

Other volunteers patrol the city looking for Russian spies and regularly questioning people walking by.

"A suspicious person is asked to say the word 'Ukrainian'. A Russian won't be able to do that," one volunteer explained.

And in Ukraine's capital Kiev, volunteers are distributing clothes and food to people displaced by the bombing.

Volunteers, and people organizing forces on the streets, are just part of Ukrainian resistance that UK intelligence claims is surprising Moscow.

"The scale and strength of Ukrainian resistance continue to surprise Russia,” the UK’s Ministry of Defense said in a tweet on Sunday.

“Russian supply lines reportedly continue to be targeted, slowing the rate of advance of their ground forces.”

The country is also seeing strong international support. Billionaire Elon Musk has sent his Starlink Internet provider systems to Ukraine to replace infrastructure damaged by bombing. — Euronews