The vote, which also included municipal and regional elections, was Chad's first in more than a decade.

Chad is led by President Mahamat Idriss Deby, who seized power after rebels killed his father, longstanding President Idriss Deby.

The vote is being held amid security challenges due to Boko Haram attacks.

Chad is an important ally for French and US forces aiming to fight rebels in the Sahel.