 The son of Chad's slain leader Idris Derby, Muhammad, has taken over as president and armed forces commander, as rebel forces threatened to march on the capital, deepening the turmoil in the country. The political opposition also denounced the military's takeover of control, calling the move a coup d'etat and rejecting its plan for a transition. Meanwhile, labor unions called on workers to go on strike. The take was backed up in the streets of Chad's capital city in Jamina on Tuesday. People here are fleeing the prospect of violence after President Idris Derby's death. Derby was killed in a battle against rebels the army had announced on Tuesday, just one day after he was declared winner of a presidential election. Derby had ruled the country for more than three decades. He was considered an important ally to the West in the fight against militants in the Sahel region. One capital city resident lamented his death. May he rest in peace. We've only known him as the country's leader. He's worked hard for the prosperity and the security of the people. Today is a difficult day for us. Derby's son, Muhammad Idris Derby, was named interim president by a transitional council of military officers, while locals expressed sadness for the loss of their former leader. Others wished the transition was led by a civilian, not the military. We don't want another military representative in power during this transition because there will be problems again. A civilian is needed. Derby took power in a 1990 rebellion and had survived numerous coup attempts. The exact cause of his death is unclear.