Nigeria is in "a serious security crisis that requires extraordinary means," the Ondo government said.
At least three people were killed in two separate attacks by gunmen in Ondo State on Thursday.
The Oluifon of Ifon in Ondo State, Adegoke Adebusi, was one of the victims as he was shot dead by the yet to be identified gunmen at Elegbeka, along Owo-Ifon Road.
The traditional ruler was said to be returning to his domain after attending a meeting of the council of traditional rulers in Akure when he was shot.
Two persons were also reportedly kidnapped at the same spot after the shooting incident.
In a separate incident also in Ondo State, two persons were shot in Ode-Irele area of Irele local government, on Thursday, when armed robbers attacked a bank and a nearby police station.
The police spokesman, Tee Leo-Ikoro, confirmed both incidents which are believed to have been carried out by different sets of armed men.
Mr Adebusi was rushed to the Federal Medical Centre in Owo, where he died of gunshot injuries.
Mr Leo-Ikoro said the commissioner of police has deployed officers to the area for possible arrest of the gunmen.
The Ondo State Government, in a statement issued by the state Commissioner for Information and Orientation, Donald Ojogo, described the murder of the monarch as unfortunate.
It said the incident had again confirmed that the country was indeed in a serious security crisis beyond the ordinary.
The state governor, Oluwarotimi Akeredolu, visited Ifon accompanied by his Chief of Staff, Olugbenga Ale; Head of Service, Dare Aragbaiye; Commissioner for Youths and Sports, Dotun Owanikin; APC Chairman Ade Adetimehin and Donald Ojogo.
"With a heavy heart, the Ondo State Government hereby confirms the unfortunate incident around Elegbeka, Owo-Ifon road in Ondo State to be true. Truly, Ondo has lost a great one-a deep cut, too sad," Mr Ojogo wrote.
"This is a heinous crime, an incident which has, again, confirmed that we are indeed, in a serious security crisis beyond the ordinary.
"All lives matter; but this is one too heavy and unbearable. It's a sad day in Ondo State. Clearly, we are in a serious security crisis that requires extraordinary means."
Mr Akeredolu, during the visit, directed security agencies, especially the Nigeria police, to arrest the perpetrators of the crime.
He said the government would do whatever it takes to apprehend the criminals.
"On our part as a government, we shall give whatever it takes to unravel this; these criminals who have wrought this sad day on our state shall not go unpunished," he said.
At Irele, witnesses confirmed the armed robbers broke into the bank after destroying the fortified entrance with explosives.
The robbery incident came hours after the Inspector General of Police left the state, after a visit to raise the morale of police officers.
The robbers who were said to have arrived at the bank around 4 p.m., also attacked a nearby police station.
After operating for about 45 minutes, they shot sporadically as they tried to get away, and two persons were hit by bullets, killing them in the process.
Several persons were also injured while trying to escape from the robbers.
It was gathered that soldiers arrived at the bank a few minutes after the robbers left, carting away undisclosed sums of cash.
The police spokesman said although he had revived the news of the robbery, he was yet to get the details from the Divisional Police Officer in the town.