The father of a state governor who defected from Nigerian President Goodluck Jonathan's ruling party escaped unhurt after gunmen attacked a mosque in his village, police said on Wednesday.
Musa Saleh Kwankwaso, whose son is Kano state governor Rabiu Musa Kwankwaso, was at the place of worship in Kwankwaso village when the attack happened at about 7:30 pm (1830 GMT) on Tuesday.
Three worshippers were killed and 12 others were injured, said Kano state police spokesman Magaji Musa Majia.
"Among the worshippers at the mosque was the district head (chief) of Madobi (local government area) and father of Kano state governor Rabiu Musa Kwankwaso, who escaped unhurt," he told AFP.
"The identity of the attackers and motive of the attack are not yet known but (an) investigation has commenced."
The banned Islamist militant group Boko Haram, fighting a four-year-long insurgency in northern Nigeria, has previously attacked mosques in Kano.
It was unclear whether the attack was politically motivated.
The younger Kwankwaso was one of five state governors to defect from the ruling Peoples Democratic Party (PDP) to the main opposition All Progressives Congress (APC) late last year.
The defections prompted 37 PDP lawmakers in Nigeria's lower house of parliament to switch allegiance to the APC, with more moves expected in the upper chamber, the Senate.
A doctor at the Aminu Kano Teaching Hospital (AKTH) in Kano, where the victims of the attack were taken, said the injured, including four children, were being treated for gunshot wounds.
One of two policemen attached to Musa Saleh Kwankwaso, who was shot in the hand, said the gunmen fired on the mosque from outside but were chased away after a shoot-out when reinforcements arrived.
"We kept firing from the windows toward any moving shadow we saw lurking around the mosque while the gunmen kept firing at the mosque, which helped in preventing them entering," he said.
In February 2012, suspected Boko Haram gunmen fired at worshippers in the Tudun Maliki area of Kano city, killing five, including a local vigilante leader.
The previous month, the state capital was the scene of the most deadly strike in the insurgency when 185 people were killed in a co-ordinated bomb and gun attack.
But there has been a lull in violence in recent months.