The explosion took place at a mosque during a Friday prayer.
“A bomb blast took place at a mosque in the Pushta Khara area,” AFP quoted a police official, Mohammad Karim Khan, as saying.
Ten of the wounded were transferred to the city's Hayatabad Medical Complex.
No one has yet claimed responsibility for the blast.
In a similar incident earlier in October, a bomb explosion at a mosque in the Takhar Province of northern Afghanistan killed a district governor along with as many as 20 people.
Pakistan has been crippled with violence and recurrent attacks in which thousands of innocent people have lost their lives.
The Pakistani army has launched several operations in the northwest of the country in an attempt to flush out pro-Taliban militants from its tribal zone.
The army believes that the militants have shifted their operations from Waziristan and the Orakzai Agency to the Kurram Agency.
Militant attacks and political unrest have claimed the lives of over 4,000 people throughout Pakistan since 2007.
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