The Trump administration slapped a Canadian judge on the International Criminal Court (ICC) with sanctions as the U.S. State Department unleashes a new wave of restrictions against judges it said had been instrumental in efforts to prosecute Americans and Israelis.

The State Department says Judge Kimberly Prost of Canada was sanctioned for ruling to authorize the ICC's investigation into U.S. personnel in Afghanistan.

ICC jurists Nicolas Guillou of France, Nazhat Shameem Khan of Fiji and Mame Mandiaye Niang of Senegal were also sanctioned, with the State Department linking the decision to the tribunal's investigation into Israel's actions in Gaza and the Israeli-occupied West Bank. As a result of the sanctions, any assets they hold in U.S. jurisdictions are frozen.

The court said on Wednesday that it deplored the sanctions, calling them "a flagrant attack against the independence of an impartial judicial institution which operates under the mandate from 125 [countries] from all regions.

"They constitute also an affront against [these countries], the rules-based international order and, above all, millions of innocent victims across the world," the statement continued. "The ICC will continue fulfilling its mandates, undeterred, in strict accordance with its legal framework as adopted by the States Parties and without regard to any restriction, pressure or threat."

In a statement, U.S. Secretary of State Marco Rubio called the court "a national security threat that has been an instrument for lawfare against the United States and our close ally Israel."

The ICC previously condemned the actions of the Trump administration, calling it an attempt to undermine the independence of an international judicial institution.

Prost joins a growing list of ICC judges facing similar sanctions.

The second round of sanctions comes less than three months after the U.S. administration took the unprecedented step of imposing sanctions on four other ICC judges.

It represents a serious escalation that will likely impede the functioning of the court and the prosecutor's office as they deal with major cases, including war crimes allegations against Russia over its invasion of Ukraine.

The ICC, which was established in 2002, has international jurisdiction to prosecute genocide, crimes against humanity and war crimes in member states or if a situation is referred by the United Nations Security Council. 

War crimes investigations

Prost served on an ICC appeals chamber that, in March 2020, unanimously authorized the court's prosecutor to investigate alleged war crimes and crimes against humanity committed in Afghanistan since 2003, including examining the role of U.S. service members.

Since 2021, the investigation has deprioritized the role of the U.S. and focused on alleged crimes committed by the Afghan government and the Taliban forces.

ICC judges issued arrest warrants for Israeli Prime Minister Benjamin Netanyahu and former Israeli defence chief Yoav Gallant last November for alleged war crimes and crimes against humanity during the Gaza conflict.

A warrant for the same alleged crimes was also issued for Hamas official Mohammed Diab Ibrahim al-Masri, also known as Mohammed Deif, who is said by the Israeli military to have been killed in July 2024

Guillou is an ICC judge who presided over a pre-trial panel that issued the arrest warrant for Netanyahu. Khan and Niang are the court's two deputy prosecutors.

Netanyahu's office issued a statement welcoming the U.S. sanctions.

Although the ICC has jurisdiction over war crimes, crimes against humanity, and genocide in its 125 member countries, some nations, including the United States, China, Russia, and Israel, do not recognize its authority.

It has high-profile war crimes investigations underway into the Israel-Hamas conflict and Russia's war in Ukraine, as well as in Sudan, Myanmar, the Philippines and Venezuela.