Schools in one Virginia county were closed Friday after a controversial homework assignment, in which students were reportedly asked to copy the Islamic statement of faith, drew backlash.

In a statement posted on the Augusta County Public Schools website, the district announced that schools would be closed Friday after “parental objections to the World Geography curriculum and ensuing related media coverage” spurred a bombardment of phone calls and emails.

The district said those messages “significantly increased in volume” Thursday and they were concerned about their “tone and content.” The district made the decision to close the schools “out of an abundance of caution,” though said there was “no specific threat of harm to students.”

The district didn’t offer details about what specific assignment prompted the backlash, but multiple media outlets reported that students at Riverheads High School were asked to practice drawing calligraphy by copying down the shahada, which is the Islamic statement of faith.

CNN published a copy of the assignment, which notes calligraphy’s importance in Islam. It shows the shahada written in Arabic calligraphy and instructs students to copy it into a box. “This should give you an idea of the artistic complexity of calligraphy,” the assignment reads.

One of the most common objections to the assignment is that the shahada, when translated into English, reads “There is no god but Allah, and Muhammad is the messenger of Allah.”

The News-Leader, a Virginia newspaper, reported that more than 100 people “met in fury” over the assignment, and some parents had called for the teacher who gave it to be fired. But the state Department of Education and the district’s superintendent both reviewed the assignment and determined it wasn’t a violation of students’ rights, and deemed it in line with state standards.

As of Friday afternoon, 2,500 members had joined a Facebook group to support the teacher. Still, some parents weren’t happy about the message the students were asked to copy.

“I will not have my children sit under a woman who indoctrinates them with the Islam religion when I am a Christian, and I’m going to stand behind Christ,” Kimberly Herndon told Virginia television station WHSV. The news station identified her as a parent of a Riverheads student.

The News-Leader reported that the teacher didn’t come up with the assignment, but rather pulled it out of a workbook about world religions. The newspaper also reported that students had learned about other religions in the teacher’s class, including Christianity and Judaism.

In its website posting, Augusta County Public Schools said “no lesson was designed to promote a viewpoint or change any student’s religious belief.” School officials said that their students will keep learning about world religions, which is required by state education officials, but a new, non-religious calligraphy sample will be used in future homework assignments about Islam.

Before making the decision to close, the district said it increased police presence at its schools.