At least seven artists hoping to play the annual South by Southwest music festival have been turned away at the US border amid confusion over the type of visa needed to enter the country.

At issue is whether artists can perform at free showcase events like South by Southwest on a B-1 visitor visa, typically issued to tourists who aren’t legally allowed to work during their visit to the US Most artists who enter the country for a tour do so on a performance visa (also known as P-1), but artists performing for free at showcase events like South by Southwest have used B-1 visitor visas in the past to enter the US.

On Monday, US Customs and Border Protection officials issued an advisory saying most artists would need a P-1 if they planned to perform in the US at promotional events like SXSW. A spokesperson for the agency provided Billboard with a statement explaining, “if an individual is a member of an internationally recognized entertainment group, they must apply for and be granted a P-1 visa.”

The statement comes after Egyptian-Canadian post-hardcore band Massive Scar Era said three of its members were denied entry into the United States on Sunday (March 13) at the US/Canada border in Vancouver, B.C. Vocalist and guitarist Cherine Amr tells Billboard that a USCBP officer informed the group that their B-1 Visas were not being accepted for entry. The Egyptian-born singer is a permanent resident in Canada, another band mate is a Canadian citizen and another enjoys First Nation status granted to individuals from indigenous groups. All three were denied entry, despite pleas with a border patrol agent that the band had played the Austin festival twice before on a B-1 visitor visa.

“He said that he knows that I’ve done everything legally, and that I’m not lying, but he’s still not going to let me in,” she tells Billboard. “He said that people are using the festival to protest, but I told him we are not going there to protest. We have no intentions of doing anything illegal or engaging in any political activity. We’re just going to promote ourselves, meet labels and bookers and network.”

Four other artists — three men with the group Soviet Soviet from Italy and the London-based drummer Yussef Kamaal — were denied entry into the country after their B-1 visitor visas were rejected. Members of Soviet Soviet were arrested at Seattle-Tacoma International Airport, detained over night in jail cells and deported back to Italy the following day.

A spokesperson for SXSW said event officials “know about the situation” and “have spoken to the artists” but are declining to comment on the visa issue. As for possible political demonstrations at SXSW, the spokesperson told Billboard “we do not know of any protests taking place at the event.”

South by Southwest officials warn on their website that travel into the United States from countries like Canada and the UK on a B-1 is often granted, but not guaranteed. Event organizers encourage artists to apply for a performance visa, even if they’re not getting paid for their appearance. Despite the warning, South by Southwest officials did issue Amr and the other band members a letter to present to US Customs officials advising that a B-1 is “appropriate when bands will be engaged only in showcasing at SXSW” because “it is not labor for hire; rather, it involves unpaid demonstrations of skills that include composition, practice and performances.”

Amr said she called the festival organizers for help at the border and attempted to hand the officer the phone, but he refused to talk to them.

“He told me ‘No, no. I am not convinced’ that South by Southwest should be played under a B-1 visa,” she said.

Amr said she was not cited and was told she would not be penalized next time she attempted to enter the country, but she said the cancelation has cost her over $1,000 and she’s concerned it will hurt her music career.

“I’m 100-percent independent and self-financed and the band is doing this without any support from a label,” she said. “I don’t know what to do. I don’t think any label or any booking agent would want to waste their time or money in a band that could be banned from entering the States.”

A version of this article originally appeared on Billboard.

UPDATE: Chilean band Trementina and Spanish rapper Yung Beef will, both scheduled to perform at SXSW, have also been denied entrance to the US due to visa issues, Billboard reports. Days before traveling to Austin, Trementina received an email informing them that their permits had been cancelled. “We tried to contact the US embassy, and they didn’t give us any answer or solution,” the band wrote on Facebook. “We’ve lost our plane tickets, a month and a half of shows, and a lot of work and time we invested in it.”

Rapper Yung Beef, who was also traveling on ESTA, was stopped at the Barcelona-El Prat airport. “We’ve canceled our participation at SXSW,” his label, La Vendicion Records, wrote on Facebook. “Yung Beef’s ESTA wasn’t accepted by the American government and we were just informed at the airport without any prior notification. Regardless of the support we’ve received from SXSW, ICEX and MINECO, we have not been able to change the status of the ESTA.”

“Now it’s not that they’re not letting me in at the club, now they’re not letting me enter a country,” Yung Beef wrote on Twitter.

Ya no eske no me dejen entrar en la diskoteka eske no ne dejan entrar en el pais

— KING BEEF (@secoweedcodein) March 14, 2017