Malian special forces arrested at least three alleged Islamist militants in the capital Bamako during the weekend, a spokesman for the army said.
Submachine guns and ammunition were found at the scene, Souleymane Maiga said in a phone interview from Bamako.
There may be more arrests in the coming days as the investigation continues, Maiga said.
The three men arrested in Bamako are alleged to have been involved in several attacks against police in Mali and one on a United Nations staff house in Bamako, he said.
Maiga named the three men as Hassan Dicko, aka Abou Leila, Ayouba Sangaré and Ali Sangaré and said they were part of the commando unit which led these attacks. Death threats had also been sent by the unit to journalists working for foreign media, he said.