Rebel Capt. Amadou Sanogo led the armed seizure of the country in March, saying the military was frustrated that the country's leaders were unable to control rebels in northern Mali. Rebels have since claimed autonomy for the region.
Ansar Dine, a group advocating Islamic law in northern Mali, and the National Movement for the Liberation of Azawad, a group led by the rebel Tuareg movement, agreed formally to create a joint Council of the Islamic State of Azawad.
A government spokesman told the United Nations' humanitarian news service IRIN that the government in Bamako rejects the creation of an Islamic state in the north.
El Hadji Baba Haidar, a lawmaker from Timbuktu, told the news service that Tuareg rebels were concealing their intentions from members of the international community.
"The MNLA (Tuaregs) tried to woo Western governments by preaching moderation and distancing itself from radical Islam," he said. "The agreement shows that the MNLA and Ansar Dine are one and the same."
An Amnesty International report said there was mass displacement, arbitrary detention, sexual violence and the use of child soldiers among rebel forces in the north of the country.
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