Kano - Four people were killed on Thursday near the home of a state governor in Gonbe State when a pick-up truck loaded with grain bags exploded, a government source told AFP.
The blast happened at about 6:30 pm near the private residence of Gombe state governor Ibrahim Dankwambo in the upscale Government Reserve area of the state capital.
"The van was moving when it exploded and killed the two men inside it and two soldiers inside the armoured vehicle stationed near the governor's personal house," the source said on condition of anonymity.
"It is not clear if the governor's house was the target or if the explosives went off prematurely before they reached their destination."
It was not immediately clear if the explosion - which was heard across the city - was the handiwork of Boko Haram or politically motivated.
Boko Haram has carried out deadly attacks in Gombe in the past.
In February 2012 Boko Haram carried out a shooting and bombing raid on a police station in the city, killing 14 people, and attempted a jail break.
In January 2012 the insurgents attacked a church in the city, killing six worshippers.
In the same month two people were killed and one injured when the insurgents opened fire on a beer parlour.
There are renewed fears of politically linked violence across Nigeria before general elections early next year.
Dankwambo is a member of the Peoples Democratic Party (PDP), which is expected to be pushed hard by the main opposition All Progressives Congress (APC) in the February 14 vote.
Gombe city is notorious for political thugs known as "Kalare" who are paid by politicians to settle scores with their opponents.