Prosecutor Fatou Bensouda's office confirmed Friday that Washington had revoked her visa for entry into the US -- a move that came after US Secretary of State Mike Pompeo announced restrictions on ICC staff who probe US or allied personnel.

A spokesperson for the EU's diplomatic service said the bloc "fully supports the ICC and its independence" and said Brussels expects the US to comply with its "international obligations" towards the court.

"The European Union reiterates its serious concern about the US policy towards the ICC," the spokesperson said in a statement.

"The ICC plays a key role in the fight against impunity. The EU emphasises that protecting the neutrality and judicial independence of the ICC is paramount to its effectiveness and proper functioning."

Bensouda asked ICC judges in November 2017 for authorisation to open an investigation into alleged war crimes in Afghanistan by the Taliban, Afghan government forces and international forces including US troops.

The court has not yet decided whether to launch a full-blown probe.

The US has never joined the ICC and does not recognise its authority over American citizens, saying it poses a threat to national sovereignty. Washington also argues that it has its own robust procedures in place to deal with US troops who engage in misconduct.