Freezing temp, clogged borders, long queues as civilians flee Ukraine. In pictures

Around 350,000 people have entered Poland from Ukraine since Russia's invasion, a Polish minister said on Tuesday.

More than 500,000 people have fled Ukraine, according to the United Nations, since Russia's invasion last week, setting off a massive refugee crisis with tens of thousands awaiting passage at European border crossings.

Piles of clothing lined the potholed road as people sought to lighten their load for the journey. (REUTERS)

More than half - around 350,000 - have fled to Poland, a bordering country and a NATO member, according to Maciej Wasik, the country's deputy interior minister who spoke to public broadcaster Polskie Radio 1.

"Over the last 24 hours 100,000 people crossed the Polish-Ukrainian border," Wasik said, "In total, since Thursday, there have already been 350,000 refugees."

Ukrainian refugees have also fled to other bordering nations, including Slovakia, Hungary and Romania, that, as members of the EU and NATO, offer safe havens ostensibly beyond Moscow's reach.

The European Union estimates that up to four million people may try to leave Ukraine because of the Russian invasion, news agency Reuters reported.

Kharkiv, Ukraine's second-largest city with 1.5 million people, was the latest to bear the brunt of the attack. Officials say dozens of people were killed and injured by missile strikes that hit civilian areas.

Piles of clothing lined the potholed road as people sought to lighten their load. (REUTERS)

Long queues form at central Europe border crossings as people flee Ukraine. (REUTERS)

(EU) estimates that up to 4 million people may try to leave the country. (REUTERS)

352 civilians have been killed in Ukraine , including 14 children, Ukrainian President said on Monday.  (REUTERS)

More than half of the Ukrainians have fled into EU and NATO member Poland. (REUTERS)

Ukrainian refugees have also fled to other bordering states Slovakia, Hungary and Romania. (REUTERS)

Thousands await passage at European border crossings. (REUTERS)

Ukraine is having devastating consequences on women and children, senior UN officials reported. (REUTERS)

Kharkiv, Ukraine's second-largest city, was the latest to face the Russian aggression. (REUTERS)

(With inputs from Reuters)