Chad's main opposition parties on Wednesday denounced what they called an "institutional coup d'etat" after the shock death of newly re-elected president Idriss Deby Itno and his replacement by son Mahamat.
Around 30 opposition formations "call for the installation of a transition led by civilians... through inclusive dialogue," the parties said in a statement.
They called on Chadians "not to obey illegitimate decisions" by the transitional military council including the naming of Mahamat as Deby's successor, a curfew and border closures.
Among the main signatories were the party of Deby's historic rival Saleh Kebzabo and Success Masra, another of his fiercest critics.
The opposition groups also warned former colonial power France, which had backed Deby since he came to power on the back of a 1990 coup in the poor Sahel country, "not to meddle in Chad's internal affairs".
They also called on the international community to "help the Chadian people restore the state of law and democracy".