The United States has revoked the entry visa of the prosecutor of the International Criminal Court, Fatou Bensouda, in response to her inquiry into possible war crimes by U.S. forces in Afghanistan.

Bensouda has been investigating alleged war crimes by all parties in the conflict in Afghanistan since November 2017, including the possible role of U.S. personnel in relation to the detention of suspects.

The office of the ICC prosecutor confirmed the revocation on Thursday and said that Bensouda would exercise her duties “without fear or favour”.

“We can confirm that the U.S. authorities have revoked the prosecutor’s visa for entry into the U.S.,” Bensouda’s office told Reuters in an e-mail.

It said it understood the move should not impact Bensouda’s travel to the U.S. to meet her United Nations obligations.

Secretary of State Mike Pompeo said last month the U.S. would withdraw or deny visas to ICC staff investigating such allegations against U.S. forces or their allies.

A State Department spokesman said members of international organizations planning official travel to the U.N. could apply for diplomatic visas. “We recommend that applicants apply as early as possible to maximize the chances of being found eligible,” the spokesman said.

United Nations human rights experts called the reaction “improper interference” in the work of the world’s permanent war crimes court. It also drew criticism from within the European Union.

The U.S. in not a member of the ICC.