More than 1.5 million people have fled Ukraine since the Russian invasion began, according to the head of the U.N. Refugee Agency, many of whom are women and children.

Across the border, in Poland, fellow moms are stepping up to help.

A now-viral photo shows a line of fully-equipped strollers waiting for Ukrainian moms at a train station at the border crossing in Medyka, Poland.

The strollers were placed there by Polish mothers, according to Francesco Malavolta, the photographer who captured the photo.

"The thing that struck me before taking the photo was the absence of people around while two meters away there were miles of people. It seemed surreal," Malavolta told ABC News by email. "I thought of them both, about the solidarity of those who brought the strollers and the dramatic stories of mothers fleeing the war."

PHOTO: Strollers for refugees and their babies fleeing the conflict from neighbouring Ukraine are left at the train station in Przemysl, at the border crossing in Medyka, Poland, on March 3, 2022.
Francesco Malavolta/AP
Strollers for refugees and their babies fleeing the conflict from neighbouring Ukraine are left at the train station in Przemysl, at the border crossing in Medyka, Poland, on March 3, 2022.

Malavolta also tweeted on Monday a photo he took showing strollers lined up at the border between Slovakia and Ukraine.

With men ages 18 to 60 forced to stay and fight in Ukraine, under a martial law order from the Ukrainian government, it is the images of mothers and children escaping the country that have captured the world's attention.

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In Medyka, a village on the border in southeastern Poland, moms and babies who have traveled for days to flee Ukraine are greeted with donated supplies, ranging from baby food to diapers and snow suits.

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PHOTO: A tent full of diapers is seen at the aid collecting point on the outskirts of Przemysl, Poland, March 3, 2022. Thousands of exhausted refugees fleeing war are arriving to the Polish border town from Ukraine.
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A tent full of diapers is seen at the aid collecting point on the outskirts of Przemysl, Poland, March 3, 2022. On the 8th day of the Russian invasion in Ukraine thousands of exhausted refugees fleeing war are arriving to the Polish border town of Przemysl from Ukraine.
PHOTO: A snow-covered child's suit and other donated baby supplies are placed in boxes for the numerous people who arrive every day in Medyka, Poland, March 5, 2022, Poland.
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A snow-covered child's suit and other donated baby supplies are placed in boxes for the numerous people who arrive every day in Medyka, Poland, March 5, 2022, Poland.
PHOTO: People fleeing the Russian invasion receive donated baby food and supplies after crossing the border from Ukraine to Poland, at the border checkpoint in Medyka, Poland, March 6, 2022.
Fabrizio Bensch/Reuters
People fleeing the Russian invasion receive donated baby food and supplies after crossing the border from Ukraine to Poland, at the border checkpoint in Medyka, Poland, March 6, 2022.

Adding to the growing humanitarian crisis, data shows, are the number of children who remain in Ukraine without guardians with whom they can flee.

Before the war, approximately 100,000 children in Ukraine were being raised in institutions, according to government statistics, a United Nations Children's Fund, or UNICEF, spokesperson told ABC News Friday.

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Many of the institutions are located in hot spots, according to the spokesperson, who added that large numbers of the children in institutions, such as boarding schools and orphanages, have disabilities.

These institutions are being evacuated without proper monitoring of the children's situation, according to UNICEF.

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