The Ethiopian government has arrested several people it says were planning attacks in the capital Addis Ababa.
Police said they arrested members of the outlawed Oromo Liberation Front (OLF) and members of a previously unknown group.
Police spokesman Demsash Hailu told the BBC the OLF members were mobilising « anti-peace activities ».
Opposition party leaders said the government was trying to implicate legitimate opposition parties.
The OLF has been fighting for independence for the southern region of Oromia for more than three decades.
The police said the men arrested were also members of legal opposition parties the Oromo National Congress and the Oromo Federal Democratic Movement (Ofdem).
ONC leader Merara Gudima confirmed the general secretary of Ofdem had been among those arrested, but said the others arrested were not members of any party.
In a second batch of arrests the police said they detained members of « Kawerj », a previously unknown Muslim group.
The BBC’s Elizabeth Blunt says the name refers to an historic Islamic movement who considered violence acceptable to depose « un-Islamic » rulers.