Rwandan police say they have arrested Diane Rwigara, a leading critic of Rwandan President Paul Kagame and a women's rights activist, for alleged offenses against state security.

Rwanda police said in a Twitter post Sunday that Rwigara's mother and sister were also detained on the tax evasion charges and she is also being charged with forgery. The three have been under investigation and police have interrogated them several times.

Her brother, Aristide Rwigara, said his sister is being persecuted for having dared to challenge Kagame, the longtime president, in Rwanda's August election.

Rwanda has won praise for its advances in economic development and women's rights over the last 20 years, but critics say Kagame rules with an iron fist and tolerates little dissent.