Citing President Donald Trump’s Muslim ban which was upheld this week by the U.S. Supreme Court, a Syrian children’s choir based in Canada canceled its plans to sing at an international festival in Washington, D.C.

“I can’t imagine that we could go if one of [the singers] got turned away at the border,” Fei Tang, the founder of the choral group, told the Middle East Eye.

The Nai Syrian Children’s Choir was established in 2016 to provide “a unique space for refugee children to learn to express their grief, yearning, love, and hope through singing in their mother tongue and in the official languages of their new home.” Young refugees from countries including Yemen, Eritrea, and Tunisia have participated in the group, and its current singers are all Syrian refugees from the ages of five to 15, according to The Guardian.

“We told the children, ‘Mr. Trump may not want us to be there in person, but nothing can stop our voices [from being] heard.'” —Fei Tang, Nai Syrian Children’s Choir founderThe choir was invited last October to sing at the Serenade! Choral Festival at the John F. Kennedy Center for the Arts in Washington, D.C. this week, but canceled its planned performance as the Supreme Court weighed President Donald Trump’s restriction on travel from several predominently Muslim nations including Syria. The ban was upheld this week in a 5-4 ruling by the Supreme Court.

All of the children have been living in Canada since at least 2016, when the country began welcoming Syrian refugees and resettling them as permanent residents. But choir leaders had heard stories of other Syrian refugees being turned away—or detained for several days—at the U.S.-Canada border.

“Some kids have been in Canada longer, some kids have fair skin, they’re blond and Christian, they probably won’t have a problem. But what if our Kurdish children or children with hijabs got stopped at the border?” Tang told The Guardian. “That’s not something we wanted to risk. It’s just too much, given what these children already have been through.”