Two male runners who were discovered fraudulently competing on behalf of female colleagues in a top South African marathon have been disqualified and could face two-year bans from the event, along with the two women.

The two women runners swapped their bibs with the two men, who both finished within the top 10 in the women’s half-marathon at the Two Oceans Marathon in Cape Town last Sunday, initially denying those slots to two female runners, according to AP.

But the cheating was discovered by a marathon board member, and the men were disqualified from their 7th and 10th place finishes. Two women were belatedly recognized instead.

Larissa Parekh was accused of having Luke Jacobs run on her behalf, and Tegan Garvey was accused of having Nic Bradfield run on her behalf, marathon board member Stuart Mann said. All four runners face disciplinary action that could include two-year bans from the event, Mann said.

Mann said both women have apologized, AP reported.

The annual Two Oceans race is one of South Africa’s iconic marathons and includes a 56-kilometer (34.7-mile) ultramarathon and a 21.1-kilometer (13.1-mile) half-marathon.

The event attracts over 16,000 participants and finishing among the top 10 is a significant achievement for most runners.