The International Criminal Court on Wednesday lashed out at the United States 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 politicised" body.

The United Nations rights chief Volker Turk and the EU's top officials threw their support behind Akane and her top officials.

Unacceptable new sanctions imposed by the USA against the International Criminal Court's President and a prosecution staff member must be lifted," said Turk.

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

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

Joining the chorus of condemnation, Spain described the court as "the cornerstone of the international criminal justice system".