Gunmen on motorbikes attacked the country house of Vice President Namadi Sambo in Zaria in Kaduna state on Monday, but he was not in the building at the time, police said.
“The policemen on guard and the assailants were engaged in a gun battle around 11:30, however, a cobbler was hit by a stray bullet and died instantly,” police spokesman Balteh Abdulrazaq said.
“Two police officers sustained bullet wounds on their legs and arms and have since been rushed to an undisclosed hospital,” he said.
Mr Abdulrazaq said no arrest has been made.
“We have already commenced investigation and we are urging the public to remain calm and report any suspicious activities around them,” he said.
Hundreds of miles northwest of Zaria in the remote city of Sokoto, suicide bombers targeted police stations on Monday.
“Two suicide bombers attacked two police formations in the state capital … as a result three people died that includes the two bombers and a police officer,” Muktar Bello, police spokesman in Sokoto, told Reuters.
Suspected members of Boko Haram killed five people and lost four of their members in a series of gun battles in Nigeria’s second largest city Kano on Sunday.
Security experts believe Boko Haram has many cells operating independently from each other. The sect recruits from the millions of disillusioned youths in the impoverished north, who can be easily coerced into joining the insurgency.