Five members of Chad's police force were killed in a raid on a militant weapon's cache in N'Djamena.
Officials say six militants also died in an explosion, as they refused to surrender and blew themselves up.
The Chadian government has blamed Nigerian armed group Boko Haram for recent violence in the country, with a bomb attack in the capital in May killing 33 people.
The militants had threatened Chad for taking part in armed operations against it in neighbouring Nigeria.
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