Human rights groups say at least five men in Egypt have been subjected to forced anal exams by the country’s Forensic Medical Authority, following the arrests of 32 men and one woman for “promoting sexual deviancy” and “debauchery” after a rainbow flag was raised during a concert in the nation’s capital. The exams, meant to determine whether a man has engaged in same-sex sexual activity, are inhumane, have no scientific justification and violate international law, according to human rights groups Amnesty International and Human Rights Watch, who are calling for release of all those arrested as part of the country’s “LGBTI crackdown.”

The 33 arrests stem from a Sept. 25 concert performed in Cairo by the Lebanese band Mashrou’ Leila, whose lead singer is openly gay, during which members of the audience raised a rainbow flag, a widely-known symbol of gay pride. Images from the concert spread on social media, leading to public outcry in the socially conservative nation where homosexuality is not explicitly outlawed, but where people who are gay or transgender (or are perceived to be) can be arrested for “debauchery” and “promoting sexual deviancy.”

The country’s top prosecutor launched an investigation into the events of the concert, and in the following days, six men were arrested and faced anal examinations. (Amnesty International reported yesterday that five exams have taken place.) One 19-year-old man was convicted on charges of debauchery and sentenced to six years in prison and six years of probation. Following the initial six arrests, an additional 26 men and one women were arrested as part of the “crackdown,” some of whom may also face exams by the Forensic Medical Authority on the basis of their perceived sexual orientation.

“Forced anal examinations are tantamount to torture—there is no scientific basis for such tests and they cannot be justified under any circumstances,” said Najia Bounaim, campaigns director for North Africa at Amnesty International, in a statement.

In a statement last year, the Independent Forensic Expert Group—a group of 35 independent forensic specialists from 18 countries working with the International Rehabilitation Council for Torture Victims—denounced forced forensic anal exams as not only inaccurate in determining a person’s sexual history, but “cruel, inhuman, and degrading treatment” that “may amount to torture depending on the individual circumstances.”

A judicial source rejected the allegations that the forensic anal exams constituted torture, according to Reuters.

“Allegations of torture or insulting those medically examined are lies not worth responding to. The examinations are carried out by a forensic doctor who swore to respect his profession and its ethics,” the source said.

Human Rights Watch published a report last year that documented forced anal exams in eight countries where same-sex conduct can be subject to prosecution: Cameroon, Egypt, Kenya, Lebanon, Tunisia, Turkmenistan, Uganda and Zambia. The report drew from interviews with 32 men and transgender women who had experienced such exams, and describes the practice as traumatic and degrading.

The report explains that the exam involves medical personnel forcibly inserting their fingers or other objects into the anus of a person who has been accused of same-sex sexual conduct and examining the shape of their anus and the tone of their anal sphincter for supposed evidence of such conduct. The report says the assertion that same-sex activity can be detected in this manner is “based on long-discredited 19th century science.”

Tunisia recently agreed to end the practice of forensic anal exams, formally accepting a recommendation at the United Nations Human Rights Council, according to Human Rights Watch. The Kenya Medical Association also recently took a public stance against any forced examinations, and resolved to organize a forum addressing the needs and rights of the LGBTQI community.

Sixteen of the 33 arrested in Egypt were tried Oct. 1 and a verdict is scheduled to be announced on Oct. 29, according to Amnesty International. Another two men are scheduled to stand trial on Oct. 11. Over 250 men have been prosecuted on allegations of promoting or engaging in same-sex activity since Abdel Fattah el-Sisi became president of Egypt in 2014.

Egypt’s official musicians union says they have banned Mashrou’ Leila from playing in Egypt again, the Associated Press reports.