An attack on the office of Chad's powerful ANSE internal security agency in the capital N'Djamena has killed several people, the government said in a statement on Wednesday.

Blaming the overnight assault on activists from the opposition Socialist Party Without Borders, headed by Yaya Dillo, the statement said that "the situation is now completely under control" and "the perpetrators of this act have been arrested or are being sought and will be prosecuted."