One by one, as prayers echoed over the Mississippi River, they sank to their knees and solemnly laid teddy bears on the snow-soaked pavement of the Stone Arch Bridge in downtown Minneapolis.

Before long a small mountain of the teddies, of all sizes and colors, took shape under overcast skies as more than 100 Ukrainian Minnesotans broke out in patriotic songs. Each bear represented one of more than 100 children killed in Ukraine since Russia launched a full-scale invasion on Feb. 24 –- an unprovoked assault that has unleashed the worst humanitarian crisis in Europe since World War II and has stoked fears of a broader conflagration in the region.

Those who converged on the bridge Sunday said the same thing, over and over again: For the sake of their children and future generations, Ukraine cannot afford to surrender its sovereignty.

"Our humanity is at stake," declared Nataliya Koppes, of St. Paul, an artist and former nurse who grew up in Ternopil, a city in western Ukraine. "It's unbearable to think that any country can attack any other country and commit horrific atrocities and get away with it. Is that the world we want to pass on to our children?"

Some expressed worry that people were becoming desensitized to the relentless barrage of grim images -– including those of wounded children and dead bodies strewn across streets. In the besieged cities of Mariupol, Kherson and Kharkiv, schools, hospitals and apartment buildings have been ravaged by rocket attacks and artillery fire.

The demonstration Sunday marked the fifth time in as many weeks that members of Minnesota's Ukrainian community have taken to the streets to call for peace. The state is home to more than 17,000 Ukrainians, many of whom have loved ones fighting in Ukraine or who have been uprooted by the bombing and shelling of civilian areas.

From living rooms in the Twin Cities, Ukrainian activists and volunteers have organized shipments of medical supplies. Using Internet tools, others have helped relatives and refugees more than 5,000 miles away escape to shelters safe from bombs and rockets.

Yet some in the close-knit Ukrainian community acknowledge they feel overwhelmed by the relentless news of death and destruction and by persistent feelings of guilt that they are not doing enough to help their compatriots in the war zone.

"The secret of the Ukrainian people is that we can't allow ourselves to just sit and cry," said Yosyf Sabir, a graphic designer and activist among Ukrainians in the Twin Cities. "The only way for justice to triumph over evil is to engage completely."

Russian strikes have left a trail of devastation across much of the nation of 44 million people. A staggering 4.1 million people –- half of them children –- have fled Ukraine since President Vladimir Putin began the onslaught six weeks ago, according to the United Nations' refugee agency. The majority have fled to neighboring countries, mostly Poland but also to Hungary, Moldova, Romania and Slovakia. Another 6.5 million people have been displaced within Ukraine, which means that fully a quarter of the nation's population has fled their homes.

Maria Doan, a Ukrainian from Minneapolis who carried a teddy bear to Sunday's rally, said her anxiety levels have been "through the roof" since the war began, when her brother and 72-year-old mother were living in Chernivtsi, a city on Ukraine's western border.

So far Chernivtsi has been spared a direct attack, but air raid sirens have become an almost daily occurrence. Each time the sirens wailed, Doan's mother would have to grab her "go bag" with extra clothes, money and documents, then scramble by foot through the city's darkened streets to a cellar-like bomb shelter.

In early March, Doan persuaded her mother to seek refuge in neighboring Moldova. Then reports began to circulate that Moldova — a former Soviet republic that is not a member of NATO — was vulnerable to attack. Fearing the worst, Doan helped her mother book a flight to Málaga, Spain, where she is staying with a close friend.

Like many Ukrainians living in Minnesota, Doan has at times grown despondent watching the daily atrocities from afar. She said the invasion took a "dark turn" for her on March 9 with Russia's bombardment of a maternity ward in Mariupol, a city on Ukraine's southern coast that has been almost entirely destroyed by Russian airstrikes.

After seeing photographs of injured pregnant woman and infants, Doan said she "wailed for an hour." The gruesome images reminded her of how Russia laid waste to cities and massacred tens of thousands in Chechnya, a small republic that sought independence, when she was a child in the 1990s.

"It is now clear that this is truly a genocide," Doan said. "I say that because there is absolutely no strategic value in attacking a maternity ward."

As a gentle snow fell on demonstrators Sunday in Minneapolis, Rabbi Daniel Ettedgui, of the Sharei Chesed Congregation in Minnetonka. read words once etched on a wall by a Jew hiding from the Nazis:

"I believe in the sun even when it is not shining/I believe in love even when not feeling it/I believe in God even when God is silent."