The International Criminal Court on Wednesday denounced new US sanctions against two more of its judges and two prosecutors, calling them a "flagrant attack" on its independence.

The four include Judge Nicolas Guillou of France, who is presiding over a case in which an arrest warrant was issued for Israeli Prime Minister Benjamin Netanyahu.

Canadian judge Kimberly Prost and deputy prosecutors Nazhat Shameem Khan of Fiji and Mame Mandiaye Niang of Senegal were also hit.

Prost was involved in a case that authorised an investigation into alleged crimes committed during the war in Afghanistan, including by US forces.

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

The ICC said it stood "firmly behind its personnel and victims of unimaginable atrocities".

It said it would "continue fulfilling its mandates, undeterred" and "without regard to any restriction, pressure or threat".

Four other judges and the court's prosecutor had already been placed under sanctions. (AFP)