After the U.S. and its partners reached a major breakthrough in delivering heavy weapons to Ukraine, Kyiv’s top law enforcement official is pushing allies to show similar determination to punish Russia in the courtroom.

“The instruments of delivering justice should be as strong as weapons we receive in order to fight for our independence,” Ukrainian Prosecutor General Andriy Kostin told The Hill. 

He is visiting Washington this week for meetings with his counterpart, Attorney General Merrick Garland, other administration officials and lawmakers to push for further U.S. support in Ukraine’s legal battles against Russia. 

Kostin’s visit follows President Biden’s decision last week to supply 31 Abrams tanks to Ukraine, in tandem with similar commitments from Germany and other NATO allies. Ukraine has now renewed its push for modern fighter jets. 

“The very difficult decisions to give us more and more weapons, really went in parallel with decisions to support us in our justice initiatives,” Kostin said.

While Biden has described Russia’s aggression against Ukraine as committing “genocide,” Kyiv wants such crimes prosecuted in an international court, plus a Special Tribunal to punish Russian President Vladimir Putin for launching an invasion of the country on February 24. 

The administration has resisted Ukraine’s push to label Russia a State Sponsor of Terrorism, but Kostin said he supports the Biden administration’s proposal to label Russia an “aggressor state,” a compromise term to avoid legal consequences of the terrorism designation. 

“Our position was, all the time, that Russia should be declared as a country, as a State Sponsor of Terrorism,” he said.

“If, going on this track, Russia would be declared as an ‘aggressor state,’ this also would be very helpful to reach justice on international level, because we are still actively fighting for the tribunal for the crime of aggression.” 

Kostin described an uphill battle in finding consensus among dozens of countries to support the establishment of a Special Tribunal, but said he expected a decision within “months,” adding that recent buy in from countries like France and the United Kingdom have helped build more consensus on the idea of prosecuting Russia for the Crime of Aggression. 

But Ukraine is looking for a clear sign from the U.S. on this issue.

“What we understand is that U.S. is also on the way, in case the U.S. [Congress] declares Russia as an aggressor state…this will be very helpful,” he said.  

Biden administration officials have not stated publicly whether they support the establishment of a Special Tribunal, but have told The Hill that they are in conversations with “Kyiv’s strongest partners as we consider Ukraine’s proposal …  as well as all other options for holding Russia and its leaders to account.”  

The Office of Prosecutor General is faced with the enormous challenge of investigating alleged Russian war crimes – with nearly 67,000 documented already, and many more expected as Ukrainian forces push to liberate additional territory from Russian occupation.

Among those are at least 155 identified cases of sexual violence, Kostin said, up from 44 cases that were identified when he was appointed prosecutor general in July. 

“Some of [the cases] are already in Ukrainian courts, some are in absentia, but the perpetrator is identified,” Kostin said. “And if we are talking about, for the sake of justice for the survivors, it’s important for them to know that this case goes to court.”

Another grievous war crime is the abduction of Ukrainian children. The head of the United Nations’ refugee agency said last week that Russia is violating the “fundamental principles of child protection” by giving Ukrainian children Russian passports and putting them up for adoption.

Kostin said that while the priority is to find and return these children to their families, the investigation of their forced relocation is part of evidence being gathered to bring the case of genocide against Russia. 

The Ukrainian government estimates that nearly 15,000 children were deported to Russia. About 126 children have been returned to Ukraine, according to their figures. 

In September, the U.S. sanctioned Russia’s Presidential Commissioner for Children’s Rights, Maria Alexeyevna Lvova-Belova, saying she has led Russia’s efforts to deport thousands of Ukrainian children to Russia.

Kostin said his office has prioritized resources to focus on these three elements: the forced deportation of children, sexual violence and genocide. 

He added that the intentional destruction of critical civil infrastructure – Russia has destroyed nearly 70 percent of Ukraine electrical grid with missile and drone attacks since October  – another element of the genocide case and that is likely to be pursued through the International Criminal Court. 

Kostin’s staff are spread across the country in nine regional offices, allowing them to quickly descend on the scene of liberated villages and cities to collect evidence of possible war crimes.

Armored vehicles help protect staff traveling to areas close to the battlefield – Kharkiv in the north, Donetsk in the east, and Zhaporizhizia and Mykoliav in the southeast. Drones are further used to scout out areas that require demining, which is carried out by trained security officials.

Assistance ranging from technical expertise to practical items such as laptops, printers and armored vehicles and demining equipment is provided by the U.S. and other partner countries, Kostin said. 

“This was all done with the help of our partners, which is very important,” he said.

But Kostin is also tasked with confronting corruption in the country that risks undermining international support and that feeds into criticism, largely from a minority wing of the Republican party, that billions of dollars of U.S. support is at risk of being misused.

Kostin called corruption Ukraine’s second enemy, along with Russia’s aggression. Last week, he accepted the resignation of his deputy, who quit in the face of public backlash for taking a vacation during war time and under questionable circumstances. 

“My position from the very first day of my appointment was that, it’s war, we need to work very actively, and we need to devote all our time to work for our country, for our nation, and if some of them didn’t understand, then it’s time for changes,” he said. 

Kostin was appointed prosecutor general in July. His predecessor was ousted by Ukrainian President Volodymyr Zelenksy after he revealed hundreds of prosecutors and security officials allegedly conspired with Russia before and during the invasion.

Rooting out collaborators is an ongoing challenge, Kostin said, as they pose risks from exposing Ukrainian military positions and putting civilians in the crosshairs to assisting Russian forces and officials exercising control in the occupied territories.

Kostin said he finds the motivations of these individuals difficult to understand, but said it could relate to Russian nationalism, money or, in the case of those under Russian occupation, being forced to betray their country under duress. 

Bringing accountability to areas liberated from Russia is incredibly difficult, sussing out those Ukrainians who willingly worked for the Russians, those collaborating under duress, or neighbors exercising personal grievances. 

“For those who stayed on the occupied territories, and started active collaboration with the occupation administration, it’s very important, also, to find all of them,” Kostin said.

“We check this information because we are fighting for justice for everyone, and it’s important for Ukrainians to understand, even if they are angry, some of them, [by] the actions of the other, we need to ensure that justice would be for all.”