Human Rights Watch is lambasting an Oscar-winning actress and other Western celebrities for attending a concert held on the birthday of Chechnya's Kremlin-backed leader, who has been accused of rights abuses.

The New York-based rights watchdog said Wednesday that American actress Hilary Swank, 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 concert hall 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.

The artists' representatives were not immediately available for comment.