0629 GMT September 18, 2021
A key ally in the West's anti-terrorist campaign in the Sahel, Deby, 68, is the frontrunner in a six-candidate race without major rivals after a campaign in which demonstrations were banned or dispersed, AFP reported.
Queuing to vote in the capital N'Djamena, a 25-year-old saleswoman named Bernadette told AFP she was voting for Deby because “thanks to him I am free to walk wherever I want, day or night, in total security”.
Polling booths and ballot boxes were arriving progressively in the city, with numerous polling stations failing to open on time.
Chad has struggled with poverty and instability since gaining independence from France in 1960.
A former rebel and career soldier who seized power in a coup in 1990, Deby has twice, with French help, thwarted attempts to oust him.
Other candidates include Albert Pahimi Padacke, a former prime minister under Deby, and Felix Nialbe Romadoumngar – officially "leader of the opposition" as his URD party has eight seats in the National Assembly.
Lydie Beassemda, a former agriculture minister, is the first woman to run for president in Chad's history.
She is pitching her campaign on federalism, in a country where ethnic rivalry is common, and on women's rights, in a culture where patriarchal domination is entrenched.
But seven other candidates were rejected by the Supreme Court and three withdrew, including longtime opposition politician Saleh Kebzabo, who quit in protest over violence by the security forces.
Deby has campaigned on a promise of peace and security in a region that has been rocked by insurgencies.
Two Chadian soldiers were killed Thursday in an ambush in the Lake Chad region, where extremists have been increasingly attacking civilians and security forces, Communications Minister Cherif Mahamat Zene said on Sunday.
Provisional results from the elections are scheduled for April 25, with the final results due on May 15.
Deby urged voters at his final rally on Friday to "turn out massively", but many residents have voiced disinterest in an election whose outcome already appears certain.
Some 7.3 million people are eligible to vote out of a population of 15 million, but the most critical opposition parties have urged voters to boycott the election.