The Muslim American Society will investigate an event at a Philadelphia Islamic Center last month at which children sang violent songs which the organization says were not "properly vetted."
The group called the incident "an unintended mistake and an oversight," the Philadelphia Inquirer reports.
A video of the event published by the Middle East Media Research Institute (MEMRI) shows children singing violent lyrics. One girl says "we will chop off their heads" to "liberate the sorrowful and exalted Al-Aqsa Mosque" in Jerusalem.
"We will defend the land of divine guidance with our bodies, and we will sacrifice our souls without hesitation. We will lead the army of Allah fulfilling his promise, and we will subject them to eternal torture," a girl reads.
Children also sang about the "blood of martyrs" and "Rebels, rebels, rebels."
"While we celebrate the coming together of different cultures and languages, not all songs were properly vetted," the Muslim American Society said in a statement on Friday. "This was an unintended mistake and an oversight in which the center and the students are remorseful. MAS will conduct an internal investigation to ensure this does not occur again."
The person in charge of the event was dismissed.
The Anti-Defamation League condemned the songs sung by the children.
"Children should not be indoctrinated to hate. These young people should never have been asked to make speeches and dance and lip-sync to songs that glorify violence against Jews and the State of Israel. The conflict between Israelis and Palestinians is deeply complex and painful on all sides, and the only chance for a peaceful future is to teach our children to pursue peace," the ADL said in a statement.