No delegates from Africa attended a summit on African trade after the visas of planned speakers and attendees were not issued ahead of the conference, VOA reported last week.

The organizer of the African Global Economic & Development Summit, an annual three-day conference held at the University of Southern California, told VOA that every single person was denied entry to the U.S.

“Usually we get 40 percent that get rejected but the others come,” said Mary Flowers, the conference’s chair. “This year it was 100 percent. Every delegation. And it was sad to see, because these people were so disheartened.”

The summit, held each year since 2013, aims to connect African businesses with U.S. investors. This year’s event focused on renewable energy, including wind and solar power projects. The conference went on last weekend as planned, but suffered from diminished attendance. Flowers told The Guardian that between 60 and 100 people from at least 12 countries were denied entry and could not attend the conference.

A State Department official declined to discuss the particulars of the would-be conference attendees’ cases.

“We do not discuss the details of individual visa cases,” the official said in an email. “Visa records are confidential under Section 222(f) of the Immigration and Nationality Act (INA). Additional information on the visa process can be found at travel.state.gov.”

The visa denials comes as President Donald Trump’s administration attempts to crack down on travel from select majority-Muslim countries. Earlier this month, Trump signed an executive order blocking travel to the U.S. from six countries, including three in Africa: Libya, Somalia and Sudan. Flowers told the Guardian that no citizens from those countries sought visas for the event.

A federal judge has blocked Trump’s order from going into effect. However, travelers from countries across the globe have faced immigration troubles and visa denials since Trump first issued a travel ban in January.

Earlier in March, several performers set to perform at SXSW were reportedly turned away at the border on their way to the festival in Austin, Texas. The same weekend, a group of musicians from Morocco canceled a performance at a New Orleans music festival after their visas were denied. Days earlier, a group of children from Ghana was denied visas to perform West African dancing and drumming in Charleston, South Carolina. In late February, several members of the Tibet women’s soccer team were denied visas to attend a tournament in Dallas.