Attorney General Merrick Garland pledged to "stand shoulder to shoulder" with war crimes prosecutors in Ukraine and said U.S. investigators had already "zeroed in" on what they say are specific crimes allegedly committed by Russian forces in an unannounced visit to a country at war.

Garland met with Ukranian President Vloydomyr Zelinsky and signed an agreement to promote information sharing about Russian atrocities that have targeted maternity hospitals, schools, and other civilian dwellings since the start of the unprovoked conflict one year ago.

"The perpetrators of those crimes will not get away with it," Garland said in remarks to a room filled with European justice ministers, presidents and other dignitaries.

The attorney general said the United States has a long memory when it comes to war crimes, pointing to a years-long effort to identify and deport Nazi war criminals who fled to America. Ultimately about 130 such cases advanced, many a generation or more after World War II ended.

Garland pointed out the Justice Department already has legal authority to prosecute people who kill U.S. citizens overseas and said DOJ has already identified several suspects. "Our prosecutors are working day and night to bring them to justice as quickly as possible," he said.

Congress recently granted DOJ the power to bring to justice other war criminals from other parts of the world so long as they're living or staying inside America's borders.

"War criminals will find no refuge in the United States," he added.

He detailed areas of close cooperation already under way with Ukraine and allies to keep track of complex streams of evidence, provide forensic help and training, and to even advise on environmental crimes that have victimized Ukrainians during the course of the ongoing conflict. Soon, Garland said, he would post a legal adviser from the U.S. to work in the country.

The meeting comes as investigators inside Ukraine are sifting through the rubble of disaster sites and exhumed graves to document evidence of mistreatment and abuse. And it also comes as the war rages on. Garland and other American officials said part of the motivation for speaking now is to deliver a message that could reach Russians waging the conflict.

The attorney general said the U.S. would support separate international efforts targeting people responsible for the crime of aggression, pointing out that effort was led by his predecessor, Robert Jackson.

He ended his remarks by pointing to a bit of personal history. His grandmother made it into the U.S. before Nazis invaded their homeland. But two of her siblings never made it out of Europe, perishing in the Holocaust. Survivors are still in the dark about what happened to them, and when.

The families of the current conflict in Ukraine "deserve to know what happened to their loved ones," Garland said. "They deserve justice."