Video of a children’s choir singing the national anthem in the U.S. Capitol, only to be unceremoniously cut off by police, spread across social media on Friday.

Capitol Police say singers from Rushingbrook Children’s Choir from Greenville, South Carolina, were stopped May 26 because of a miscommunication. Musical performances in the hallowed seat of Congress require permission, and police said officers had been unaware that the choir had approval from the House speaker. Capitol Police denied choir leaders’ claims that the performance was stopped because it might be found offensive.

Choir Director David Rasbach and Micah Rea, a choir leader who helped organize the trip, told The Associated Press that they worked with the offices of Reps. William Timmons, Joe Wilson and Russell Fry, all Republicans from South Carolina, to get permission for the performance. They said they were informed the visit was approved by the office of House Speaker Kevin McCarthy, R-Calif.

After stopping by Wilson’s office for photos, the group went on a tour of the Capitol that ended in Statuary Hall, famous for housing a collection of statues donated by each of the 50 states, where the choir began to perform. A visitor guide asked if they had permission for the show, Rasbach and Rea said, and told them they could start singing once he conferred with someone else.

The video shows the children concluding the first verse of the anthem as onlookers applauded. But as they started another verse, an officer can be seen talking with Rea and another man. About a minute later, a man identified as a staffer for Wilson approached Rasbach to stop the singing.

“When they stopped us, and I walked over to the Capitol Police, I said, ‘Why are you stopping us?’” Rasbach said. “They said, ‘Because this is considered a demonstration, and we don’t allow demonstrations in the Capitol.’”

Rasbach claimed that a Capitol Police officer later told him that there were also concerns that people could be offended, but he was unable to provide the name of the officer or otherwise substantiate that assertion.

Capitol Police initially issued a statement saying they were under the impression the group didn’t have permission to perform in the building. They later issued a second statement saying there had been a “miscommunication” and that the police “were not aware that the Speaker’s Office had approved this performance.”

Musical performances are among the activities specifically listed as requiring a special permit from the Capitol Police, along with demonstrations such as marches, rallies and vigils, any filming or photography for commercial uses and foot races, according to a policy posted on the agency’s website.

“Although popup demonstrations and musical performances are not allowed in the U.S. Capitol without the proper approval, due to a miscommunication, the U.S. Capitol Police were not aware that the Speaker’s Office had approved this performance,” the second statement reads. “We apologize to the choir for this miscommunication that impacted their beautiful rendition of the Star-Spangled Banner and their visit to Capitol Hill.”

In their initial statement about the event, Capitol Police addressed the claim that the show was stopped because it could be offensive.

“Recently somebody posted a video of a children’s choir singing the Star-Spangled Banner in the U.S. Capitol Building and wrongfully claimed we stopped the performance because it ‘might offend someone.’ Here is the truth. Demonstrations and musical performances are not allowed in the U.S. Capitol. Of course, because the singers in this situation were children, our officers were reasonable and allowed the children to finish their beautiful rendition of the Star-Spangled Banner,” the statement said.

McCarthy and three South Carolina representatives who had worked with the choir confirmed that the speaker’s office had invited the choir to the Capitol.

“We recently learned that schoolchildren from South Carolina were interrupted while singing our National Anthem at the Capitol,” they said in a joint statement issued to the AP. “These children were welcomed by the Speaker’s office to joyfully express their love of this Nation while visiting the Capitol, and we are all very disappointed to learn their celebration was cut short.”