Buhari made this declaration on Monday while addressing a meeting of the All Progressives Congress (APC) Caucus in Abuja before the discussions went into a closed-door session.
The President said he had ordered security agencies to prepare to crack down on potential trouble makers during the rescheduled elections.
He warned, “I have briefed the law enforcement agencies and the military. They have identified the hot spots, flashpoints.
“They should be prepared to move. We have made as much arrangement as possible and resources provided as much as the country can afford.
“Anybody who decides to snatch ballot boxes or lead thugs to disturb it, maybe this is the last unlawful action you will take.
“I really gave the military and the police (order) to be ruthless. We are not going to be blamed that we want to rig election. I want Nigerians to be respected. Let them vote whoever they want across the parties.
“I am going to warn anybody who thinks he has enough influence in his locality to lead a body of thugs or to disturb the voting system, he will do it at the expense of his own life.”
The President also vowed to put machinery in place to unravel the circumstances that led to the postponement of the 2019 General Elections, which was earlier scheduled to hold on Saturday, February 16 and March 2nd 2019.
President Buhari wondered why the Independent National Electoral Commission (INEC) would come up with the excuses it gave for postponing the elections when it had all the time and resources to conduct the elections.
He added that the decision by INEC would have been excusable if the National Assembly did not approve the funds required for the elections.
“Definitely, the reasons why certain incompetence manifested itself has to be explained to the nation. After the election, we have to know exactly what happened, and who is responsible; otherwise our efforts to make sure that this system that we voluntarily accept, is not making progress. What is the use if we accept incompetence?” he asked.