Egyptian security forces killed three gunmen on Tuesday, the interior ministry said, in a raid on a hideout used by what it described as an armed wing of the Muslim Brotherhood.
It said in a statement on Facebook that automatic weapons were found in the house in the southern province of Assiut, which was used by a recently emerged armed group called Hasm.
Hasm claimed responsibility in September for an assassination attempt on a senior prosecutor, saying it was in revenge for mass death sentences against political prisoners.
Egyptian judges have issued death sentences against hundreds of Muslim Brotherhood supporters since mid-2013, when President Mohamed Mursi, a member of the group, was overthrown by the army and immediately arrested.
The Brotherhood, which won Egypt's first free elections after the 2011 uprising that ended Hosni Mubarak's 30-year rule, has since been banned and its leaders and members have largely been imprisoned or driven into exile or underground.
Since the crackdown, other small groups, including Hasm, have popped up and carried out attacks on police, prosecutors and army officers.
The government says these groups are linked to the Brotherhood. The Brotherhood says it is a peaceful organisation.