The Hague, Netherlands - The International Criminal Court on Wednesday lashed out at the US after Washington slapped sanctions on ICC President Tomoko Akane, calling it a "flagrant attack" on the court's independence.

The US sanctioned Akane of Japan and trial lawyer Abdoulaye Seye of Senegal on Tuesday, as part of Washington's campaign against what it calls a "corrupt and fatally politicized" body.

The EU's top officials immediately threw their support behind Akane, saying they "stand firmly" with the ICC president and her top officials.

In twin statements on X, European Commission chief Ursula von der Leyen and European Council head Antonio Costa said the court "must be able to act independently and without external pressure."

Germany echoed the stance, with its foreign ministry calling the court's independence "of central importance"; while the Netherlands, which hosts the court at The Hague, also voiced its disapproval.

The court said in a statement: "These sanctions are a flagrant attack against the independence of an impartial judicial institution."

"Such measures targeting judges, prosecutors and staff... undermine the rule of law," it added.

Washington's latest move follows other sanctions it imposed on several ICC officials, seen as largely in response to the court's investigations involving Israel, a US ally.

Japan also objected to the sanctions, saying the country has "consistently supported the ICC... in its efforts to prosecute and punish the most serious crimes of concern to the international community and to uphold the rule of law."

The measures are "very unfortunate," foreign ministry press secretary Toshihiro Kitamura said in a statement.

Japan is the biggest funder of the ICC and a close US ally – which is not a party to the international treaty that established the court.

US Secretary of State Marco Rubio earlier said in a statement, without providing examples, that the sanctioned "individuals have directly engaged in efforts by the ICC to investigate, arrest, detain, or prosecute officials whose government has not consented to ICC jurisdiction."

Established in 2002, the ICC prosecutes individuals accused of the gravest atrocities and acts as a last resort when countries do not have adequate legal systems to ensure accountability.