On the first day of campaigning, the capital N'Djamena was decked out in his political colours and giant portraits of President Mahamat Idriss Deby Itno, an AFP journalist observed.

"I am a soldier and a man of the field... after three years at the head of the country, I have experience," said Itno in front of thousands of supporters gathered in Nation Square, a stone's throw from the presidential palace.

General Itno, 40, was proclaimed president by a junta of 15 generals in 2021 following the death of his father Idriss Deby Itno, who had ruled the Sahel country with an iron fist for more than three decades.

The new president promised to hand power back to a civilian government within 18 months and told the African Union he would not stand for election as president.

But he then extended the transition period by two more years and in March officially announced he would run for the top office.

Last month 10 candidates -- including two fierce opponents of the military regime -- were barred from standing in the presidential election.

Only former opponent Succes Masra, now prime minister, remains in the race. His participation has been denounced by the opposition as a front for plurality.

A former opposition leader, Masra signed a reconciliation deal with the junta leader earlier this year.

He held a meeting in front of a few thousand supporters in his neighbourhood and intends to conduct a "door-to-door campaign".

The opposition has accused Masra of betraying them to form a majority with Itno and ultimately secure a place in government.

Itno's main rival Yaya Dillo Djerou was shot dead in an army assault on his PSF party headquarters in late February.

The election has been scheduled for May 6.