The United States on Thursday condemned South Africa's recent detention of U.S. officials who it said were providing support to the Afrikaner minority group.

Two U.S. Citizenship and Immigration Services refugee officers were briefly detained and then released during the operation on Tuesday, a USCIS official and a person familiar with the matter told Reuters.

South Africa's home affairs ministry said no U.S. officials were arrested.

On Wednesday, South African authorities said they arrested and would deport seven Kenyan nationals illegally working on processing refugee applications for the U.S. government.

"The U.S. condemns in the strongest terms the South African government's recent detention of U.S. officials performing their duties to provide humanitarian support to Afrikaners," the State Department said in a statement, referring to South Africa's Dutch-descended minority group.

President Donald Trump's administration aims to bring thousands of white South Africans to the United States on the basis of claims that they are victims of racial persecution, which South Africa's government denies.

During his second term, Trump has repeatedly made false claims about South Africa's treatment of its white minority, and used this as a justification for cutting aid and excluding South Africa from G20 meetings.

The State Department said on Thursday that U.S. officials' passport information had also been publicly released in what it called "an unacceptable form of harassment."

"We call on the Government of South Africa to take immediate action to bring this situation under control and hold those responsible accountable," the State Department said.

South Africa's foreign affairs ministry responded that it had noted "an unsubstantiated allegation regarding the private information of U.S. officials".

"South Africa treats all matters of data security with the utmost seriousness ... We categorically reject any suggestion of state involvement in such actions," the foreign affairs ministry said in a statement.

It added that it would seek further clarity from the U.S. government via official channels and that it would make the point that "bilateral engagements must be grounded in mutual respect and factual dialogue".