A bomb went off in the Gamboru market in Nigeria's northeastern city of Maiduguri on Sunday, a resident and a military source said.
One person was killed, a hospital source told Reuters. Three others were injured, the military source said.
On Saturday a suicide bomber blew himself up inside a mosque after Boko Haram militants attacked the outskirts of the city overnight. At least 29 people were killed.
The military source said the explosives in Sunday's blast were concealed in a bag of charcoal inside the market, about 300 meters from the state customs office.
There was no immediate claim for the blast, which is typical for such attacks, but it bore the hallmarks of Boko Haram.
The capital of Nigeria's Borno state, home to about 2 million people, is the birthplace of the six-year Islamist insurgency waged by Boko Haram to carve out a state adhering to strict sharia law.
"I heard the sound of a bomb explosion inside Gamboru market as I approached the area to buy vegetables. An ambulance later brought out four people seriously injured," Felicia Emmanuel, a resident, said.
The group is showing a return to its guerrilla tactics since losing the territory it gained in 2014 after successful offensives by Chadian, Nigerien and Nigerian troops over the past few months. It maintains a last stronghold in the Sambisa forest reserve.