Controversy has erupted at the annual South by Southwest (SXSW) arts festival after U.S. Olympic fencer Ibtihaj Muhammad was asked to remove her hijab, or Muslim head covering, in order to get into the event.

Muhammad was in the process of picking up her identification badge at the event on Saturday when a volunteer denied her entry unless she removed her hijab for the photograph, according to a Reuters report.

Muhammad said the volunteer ignored her when she said she wore it for religious reasons, indicating on Twitter that the volunteer continued to insist on the hijab’s removal.

The incident has led SXSW organizers to apologize and remove the volunteer from the event. They said in a statement they were embarrassed about the incident and had apologized to Muhammad personally.

Muhammed will be competing at the Olympics this summer in Rio de Janeiro as the first Olympian to represent the United States while wearing a hijab.

Meanwhile, the festival announced that the Obamas would be attending SXSW. It will be the first time a sitting President and the First Lady will participate in the event when they deliver the opening keynote at SXSW music on March 16.

“This marks the first time in the 30-year history of SXSW that a sitting President and the First Lady have participated in the event, which is known for showcasing the most innovative ideas and creative talent of our time,” a statement reads. “Over the past 30 years, SXSW has become the premier destination to discover gamechanging new technologies, films, and artists while networking with some of the brightest minds where ideas and topics converge to unite all industries and cultures.”