The detained wife of leading Mongolian activist Hada met with her brother in north China for the first time in months, as authorities continue to harass her family, a rights group said Friday. Xinna and her son Uiles were arrested in December in Hohhot city in Inner Mongolia, just as her husband Hada was due to complete a 15-year jail term, the Southern Mongolian Human Rights Information Centre (SMHRIC) reported. But Hada was never released, and his wife and son were later charged respectively with \"illegal business practices\" and \"drug possession,\" rights groups have said. Both have denied the charges and maintained their innocence, according to the SMHRIC. The group said Xinna\'s brother visited her Tuesday at a detention centre in Hohhot, where she is held separately from her son and husband -- the first time in over four months that a relative has been allowed to meet with a Hada family member. The detention centre refused to comment when contacted by AFP. One of China\'s longest-jailed prisoners of conscience, Hada was jailed on separatism and espionage charges after writing essays on greater Mongol autonomy and organising peaceful demonstrations. Many of China\'s six million ethnic Mongols, who have cultural and ethnic ties with Mongolia, complain of political and cultural repression. That resentment flared up in May and June, when the region was hit by widespread protests over resource exploitation and Chinese rule. The arrests and continued detention of Hada\'s family appear to reflect government concerns of further ethnic unrest in Inner Mongolia. \"Despite the lack of evidence, the Public Security Bureau told us that Xinna needs to be held in detention for some time,\" Xinna\'s mother Hanshuulan told the SMHIRC over the phone. \"We are not allowed to visit Hada and Uiles. But we are still demanding a meeting with both of them.\" Hanshuulan said public security personnel had been visiting her and her daughter Naraa regularly. She added Naraa had been asked to write letters to Hada stating that all of his relatives were no longer supporting him and trying to stay away from him, but she refused. She has also been threatened that she will be thrown in jail if she continues to give information about the family to foreign journalists and human rights groups.