JOHANNESBURG -- Rights groups are lobbying rapper Nicki Minaj to cancel her upcoming concert in Angola, a southern African country often criticized for human rights abuses.

According to local media reports, Minaj is set to perform in the capital, Luanda, in a holiday season concert organized by Angolan mobile phone company Unitel. The award-winning rapper also tweeted that she would be in Angola this Saturday.

The Human Rights Foundation wrote a letter to Minaj asking her to cancel her performance and instead support a local rapper who was jailed along with other youth activists.

The Robert F. Kennedy Human Rights group said Minaj would be taking money from a dictatorship that has cracked down on freedom of expression.

President Jose Eduardo dos Santos has ruled the oil-rich country for 36 years.