The International Criminal Court says it will "continue to do its work undeterred" a day after US National Security Adviser John Bolton threatened sanctions if the tribunal investigated US activities in Afghanistan.
The Hague-based court said in a statement on Tuesday it was an independent and impartial institution with the backing of 123 countries.
"The ICC, as a court of law, will continue to do its work undeterred, in accordance with those principles and the overarching idea of the rule of law," it said.
ICC prosecutor Fatou Bensouda said last year there was a "reasonable basis to believe" war crimes and crimes against humanity were committed in Afghanistan and that all sides in the conflict would be examined, including members of the US armed forces and Central Intelligence Agency.
Bolton said on Monday that if such an investigation was launched, the Trump administration would consider banning ICC judges and prosecutors from entering the United States, sanctioning funds they have there and prosecuting them in US courts.
The United States did not ratify the Rome treaty that established the ICC during the presidency of Republican George W. Bush. Instead, it adopted the American Services-Members' Protection Act, nicknamed the Hague Invasion Act because it authorised the use of any means necessary to free US personnel held by the court.
The Trump administration also said the Palestinian Liberation Organisation's office in Washington would be closed for seeking to punish Israel through the ICC.
"The United States will use any means necessary to protect our citizens and those of our allies from unjust prosecution by this illegitimate court," Bolton told the Federalist Society, a conservative group, on Monday.
It was his first major address since joining US President Donald Trump's White House in April.
The Palestinians said they were undeterred from going to the ICC.
Australian Associated Press