MOSCOW (AP) — An international human rights watchdog lambasted an Oscar-winning actress and other Western celebrities on Wednesday for attending a concert held on the birthday of Chechnya’s Kremlin-backed leader, who has been accused of grave rights abuses.

The New York-based Human Rights Watch said that American actress Hilary Swank (pictured), Belgian actor Jean Claude Van Damme and British violinist Vanessa Mae attended the concert in the Chechen capital, Grozny. The Oct. 5 show was held at a police-cordoned stage on Chechen leader Ramzan Kadyrov’s 35th birthday.

Human Rights Watch urged the artists to “avoid legitimizing people like” Kadyrov, who has been accused by rights groups of having orchestrated abductions, extrajudicial killings and the enforcement of sharia law in Chechnya, a Russian republic.

“Ramzan Kadyrov is linked to a grim record of abuse,” the group’s Europe and Central Asia director Huge Williamson said in a statement. “When stars get paid to turn up to party with (Kadyrov), it trivializes the suffering of countless victims of human rights abuses.

The artists’ representatives were not immediately available for comment.

Kadyrov is a former separatist rebel who changed sides before the second Chechen war started in 1999. Respected human rights groups have documented disappearances, house torchings and extra-judicial killings, and say they have evidence of Kadyrov’s direct participation in torturing crime suspects.