The death of the four policemen was caused by an ambush by gunmen in Tombo ward of Logo Local Government area of Benue State.
The anti-riot policemen were deployed to check the wanton killings in the state.
The attack in which two police vehicles were set ablaze, happened on Sunday.
The Benue State Police spokesman, Mr. Moses Yamu, said four riot policemen were killed by the ``insurgents”.
In Kano, the police have launched a manhunt for the killers of a policeman during the abduction of a German on Monday.
The gunmen killed the policeman and abducted the expatriate engineer with Dantata and Sawoe Construction company.
Eyewitnesses said the incident took place at about 7.45am on Ring Road bypass in Kano metropolis.
Three gunmen came in a black VW Golf, first shot at the Police escort and kidnapped the expatriate engineer, who is supervising the road construction.
The Kano Police spokesman Magaji Musa Majia said they were displeased with the ugly situation.
”The attackers killed one police sergeant attached to the Special Protection Unit (SPU) on escort duty and abducted Mr. Michael Cremza, a German working with the company.
``The Police Commissioner, Mr. Rabiu Yusuf, has since deployed powerful team of operatives and detectives to cordon the axis with a view to arresting the culprits and rescue the victim,“ he said.