A presidential decree declared late Wednesday that the director generals of both the police and military police, the chiefs of general staff of the armed forces as well as the commanders of the national nomadic guard had all been "called to other functions".

It follows Saturday's announcement on state television that Security Minister Mahamat Charfadine Margui had been replaced by a general, Ali Ahmat Akhabache.

The reshuffles come against the backdrop of a deteriorating political and security climate in the central African country.

The killing of a former commander of general intelligence and his son by unidentified armed men prompted an official order last week "to secure the city of N'Djamena" and carry out "systematic searches" for weapons.

Heavily armed soldiers were deployed in parts of the capital to conduct the searches.

Opposition parties also announced last week that they would refuse to take part in parliamentary and local elections on December 29, denouncing a "harmful climate of dictatorship and of terror".

General Deby Itno was proclaimed transitional president in April 2021 by a junta of 15 generals after his father, iron-fisted president Idriss Deby Itno, had been shot dead by rebels following 30 years in power.

After a new constitution was approved in a referendum in December, Deby Itno, 40, was elected president in May in elections that the opposition boycotted and international observers said were not credible.