Jammeh has vowed to stay in power despite losing a Dec. 1 election to rival Adama Barrow, raising the possibility that regional powers may intervene to oust him if diplomacy does not succeed in persuading him to leave.
"We have put standby forces on alert if he does not (step down) on Jan. 19 when his mandate ends," De Souza said on Malian state television on Thursday evening. "No one has the right to oppose the will of the people."
Barrow's surprise victory and Jammeh's initial decision to concede after 22 years in power was seen across Africa as a moment of hope. But the president changed his mind a week later and said again on Tuesday that he would not step down, rebuffing efforts by West African leaders to persuade him.