Egypt arrested seven people on Monday after they raised the rainbow flag at a concert in Cairo, causing an outcry against homosexuality in the conservative North African country.

The seven face charges of inciting immorality and promoting homosexuality, a security source told DPA.

Security forces identified the seven through footage on surveillance cameras at the concert venue, where the Lebanese rock band Mashrou' Leila performed on Friday.

Pictures and videos shared on social media showing audience members raising the rainbow flag - a symbol of the LGBTQ (lesbian, gay, bisexual, trans and queer) movement - caused controversy in Egypt.

While homosexuality is not a crime under Egyptian law, it carries a social stigma in the country. There have been several cases of gay men convicted of immorality or contempt of religion.

Earlier on Monday, Egypt's music syndicate had threatened to ban performances by Mashrou' Leila, whose front man, Hamed Sinno, is openly gay.

"This is rotten art. The syndicate aims at supporting serious art; art with a purpose. We support art that maintains the values of the society," Reda Ragab, first deputy of the Musicians' Syndicate, told DPA.

Ragab said he held a meeting with other syndicate officials and they "decided to ban any permits allowing Mashrou' Leila to hold any concerts in Egypt."

The decision awaits the syndicate board's approval, he added.

Foreign bands need several permits to be able to perform in Egypt, including approvals by the syndicate and the censorship body. They also need approval by the public Security department, which has the final say, according to Ragab.

The band said it had been banned from performing in Jordan.

In Egypt, a court convicted 11 gay men last year of "inciting debauchery." They received sentences of between three and 12 years.

In 2014, 26 men were accused of taking part in a homosexual orgy in a Cairo bathhouse, though they were cleared a few months later.