A South African university suspended two students for painting their faces in what it called a "blackface" incident deemed to be racially offensive. One of the students, however, says they were dressing as purple space aliens for a party with a galactic theme.

The episode at Stellenbosch University comes amid heightened debate on social media about racism in South Africa, which became a multi-racial democracy after the end of white minority rule in 1994.

Spokesman Martin Viljoen said Monday that the university is aware of "new evidence" — a reference to the account about alien costumes — and that an investigation is ongoing.

One photograph of the students, posted on social media, shows them with dark face paint. Another photo shows a woman with purple face paint and blue lips.