Heavy gunfire had been heard on Wednesday in the capital N'Djamena near the headquarters of Dillo's party, according to witnesses.
The gunfire heard near the opposition offices came after several people were killed in earlier clashes near the country's internal security agency building.
The violence flared amid tensions ahead of a presidential election set for May and June that could return the Central African nation to constitutional rule three years after military authorities seized power.
On Thursday morning, calm had returned to the capital and residents were returning to work, though internet access, which was blocked a day earlier, had still not been restored, witnesses confirmed.
More updates to come.
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