The Justice Department has quietly informed European officials that the United States is withdrawing from a multinational group created to investigate leaders responsible for the invasion of Ukraine, including President Vladimir V. Putin of Russia, according to people familiar with the situation.
The decision to withdraw from the International Center for the Prosecution of the Crime of Aggression against Ukraine, which the Biden administration joined in 2023, is the latest indication of the Trump administration’s move away from President Joseph R. Biden Jr.’s commitment to holding Mr. Putin personally accountable for crimes committed against Ukrainians.
The group was created to hold the leadership of Russia, along with its allies in Belarus, North Korea and Iran, accountable for a category of crimes — defined as aggression under international law and treaties that violates another country’s sovereignty and is not initiated in self-defense.
The decision, the people familiar with the situation said, is expected to be announced on Monday in an email to the staff and membership of the group’s parent organization, the European Union Agency for Criminal Justice Cooperation, better known as Eurojust.
The United States was the only country outside Europe to cooperate with the group, sending a senior Justice Department prosecutor to The Hague to work with investigators from Ukraine, the Baltic States and Romania.
A department spokesman did not immediately respond to a request for comment on Sunday night.
The Trump administration is also reducing work done by the department’s War Crimes Accountability Team, created in 2022 by the attorney general at the time, Merrick B. Garland, and staffed by experienced prosecutors. It was intended to coordinate Justice Department efforts to hold Russians accountable who are responsible for atrocities committed in the aftermath of the full invasion three years ago.
“There is no hiding place for war criminals,” Mr. Garland said in announcing the organization of the unit.
The department, he added, “will pursue every avenue of accountability for those who commit war crimes and other atrocities in Ukraine.”
During the Biden administration, the team, known as WarCAT, focused on an important supporting role: providing Ukraine’s overburdened prosecutors and law enforcement with logistical help, training and direct assistance in bringing charges of war crimes committed by Russians to Ukraine’s courts.
The team did bring one significant case. In December 2023, U.S. prosecutors used a war crimes statute for the first time since it was enacted nearly three decades ago to charge four Russian soldiers in absentia with torturing an American who was living in the Kherson region of Ukraine.
In recent comments, President Trump has moved closer to Mr. Putin while clashing with Ukraine’s president, Volodymyr Zelensky — going so far as to falsely suggest that Ukraine played a role in provoking Russia’s brutal and illegal military incursion.
“You should have never started it,” Mr. Trump said in February, referring to Ukraine’s leaders. “You could have made a deal.” He followed up in a post on social media, calling Mr. Zelensky a “Dictator without Elections” and saying he had “done a terrible job” in office.
The Trump administration gave no reason for withdrawing from the investigative group other than the same explanation for other personnel and policy moves: the need to redeploy resources, according to the people familiar with the situation, who spoke on the condition of anonymity because they were not authorized to discuss the moves publicly.