Authorities said it was too early to say who was behind the violence but observers suggested a link to local politics rather than Boko Haram, the Islamist insurgents terrorising north Nigeria who are holding more than 200 schoolgirls captive.
The scene of yesterday's blast in the mainly Christian district of Sabon Gari was cordoned off, with armed police and soldiers on guard and allowing only local residents back home.
Police meanwhile said officers had averted another car bomb attack in the city after stopping a car packed with material for a home-made bomb.
"The vehicle was recovered at Tafawa Balewa Street, (in the) Nasarawa area of Kano state, and has since been rendered safe by police bomb disposal experts.
Also Read
"Meanwhile, security agencies in Kano have commenced (an) investigation into both the aborted blast as well as last night's bomb incident."
Yesterday's attack happened at about 0230 IST in the Middle Road area of the neighbourhood, when the busy area was packed with revellers at its many bars and restaurants.
Kano police commissioner Adelere Shinaba told reporters that it was soon early to say who was responsible for the attack, which is the second time in less than a year that Sabon Giri has been targeted.
Three men and a young girl aged 12 were killed in the blast, he added. Seven others were injured.
Last July, a series of explosions rocked the Sabon Gari area, killing 12 with outdoor bars the apparent target. The military at the time blamed Boko Haram Islamists for carrying out the bombings.
But some observers were quick to make a link between the blast and local government elections held in Kano on Saturday, at which the main opposition All Progressives Congress (APC) won all 44 seats.
The last local elections were held seven years ago and the announcement of the results triggered widespread violence. Security had been tight in the city in the run-up to the latest poll.
Northern Nigeria has been hit by five years of increasingly bloody attacks at the hands of Boko Haram and a mounting civilian death toll.