The prosecutor of the International Criminal Court said Friday that her U.S. visa has been revoked, in what appears to be evidence of a crackdown on the global tribunal by the Trump administration.

In a statement confirming the revocation, prosecutor Fatou Bensouda's office stressed that she "has an independent and impartial mandate" under the court's founding treaty, the Rome Statute.

"The Prosecutor and her office will continue to undertake that statutory duty with utmost commitment and professionalism, without fear or favour," the statement said.

Bensouda's office said that the revocation of her visa shouldn't have an impact on her travel to the U.S. for meetings, including regular briefings at the UN Security Council. The U.S. has never been a member of the ICC, a court of last resort that prosecutes grave crimes only when other nations are unwilling or unable to bring suspects to justice.

Bensouda is expected to brief the Security Council next month on her investigations in Libya.

The U.S. State Department confirmed the measure regarding her visa.

"In this case, where Prosecutor Bensouda has publicly stated that her visa has been revoked, we confirm that the Prosecutor's visa to the United States has been revoked," the department said in a statement.

It declined to discuss other cases but said that "the United States will take the necessary steps to protect its sovereignty and to protect our people from unjust investigation and prosecution by the International Criminal Court."

U.S. sovereignty threatened: Pompeo

U.S. Secretary of State Mike Pompeo said last month that Washington would revoke or deny visas to ICC staff seeking to investigate alleged war crimes and other abuses committed by U.S. forces in Afghanistan or elsewhere and may do the same with those who seek action against Israel.

The ICC prosecutor has a pending request to look into possible war crimes in Afghanistan that may involve Americans. The Palestinians have also asked the court to bring cases against Israel.

Pompeo said in March that his move was necessary to prevent the court from infringing on U.S. sovereignty by prosecuting American forces or allies for torture or other war crimes.

Bensouda asked last year to open an investigation into allegations of war crimes committed by Afghan national security forces, Taliban and Haqqani network militants, as well as U.S. forces and intelligence officials in Afghanistan since May 2003.

The request says there is information that members of the U.S. military and intelligence agencies "committed acts of torture, cruel treatment, outrages upon personal dignity, rape and sexual violence against conflict-related detainees in Afghanistan and other locations, principally in the 2003-2004 period."

Secretary of State Mike Pompeo, centre, and national security adviser John Bolton, right, seen with Donald Trump earlier this year, have both criticized the ICC and threatened its officials with sanctions. (Evan Vucci/Associated Press)

The United States has never been a member of the Hague-based court, even though the Clinton administration in 2000 signed the Rome Statute that created it. However, he had reservations about the scope of the court's jurisdiction and never submitted it for ratification to the Senate.

When President George W. Bush took office in 2001, his administration passed the American Service Members Protection Act, which sought to immunize U.S. troops from potential prosecution by the ICC. In 2002, U.S. national security adviser John Bolton, then a State Department official, travelled to New York to ceremonially "unsign" the Rome Statute at the United Nations.

In a speech to the American Society of International Law late last month, ICC President Chile Eboe-Osuji paid tribute to American involvement in previous international courts, from the post-Second World War trials of Nazis in Nuremberg to UN tribunals for the former Yugoslavia and Rwanda.

He urged Washington to support the ICC "whose values and objectives are entirely consistent with the best instincts of America and her values."