Police officer Mohammad Ashfaq said at least 45 people were injured in the April 29 attack, which occurred near a bus stop.
Peshawar city police chief Liaqat Ali Khan said the bomber, who was riding a motorcycle, detonated his explosives as a police patrol passed nearby.
"I was in a bus when I heard the explosion and saw a flash of light," one of those injured in the blast, Masaud, told RFE/RL's Radio Mashaal. "I was injured and I saw a lot of people who were killed and injured, some of them [had their clothes blown off]."
The attack appeared aimed at the convoy of a city official who had passed by shortly before the explosion.
Afghanistan's consul to Peshawar, Sayed Mohammad Ibrahim Khel, told RFE/RL's Radio Free Afghanistan that the blast killed a member of the Afghan Chamber of Commerce delegation in Peshawar and an employee from the office of the Afghan attache on refugees affairs.
"In the morning today, an incident took place on Arbab Road [in Peshawar], in which Hilal Ahmad Waqad and a local employee [named] Edris, were martyred," Khel said.
Hilal Ahmad Waqad was the son of Afghan cleric Amin Waqad, a member of Afghanistan's High Peace Council, which is trying to engage the Afghan Taliban in peace talks.
The consulate said Hilal Ahmad Waqad was organizing a conference of Afghan and Pakistani religious scholars to oppose militancy.
The consulate said Hilal Ahmad Waqad was organizing an antimilitancy conference of Afghan and Pakistani scholars.
Reports said many of the casualties came from a bus damaged in the blast. A police vehicle was also damaged.
No one has claimed responsibility for the attack.
It follows weeks of intense bloodshed aimed at derailing national elections on May 11, set to be the first vote in Pakistan's turbulent history that leads to a peaceful transition from one civilian government to another.
The Pakistani Taliban has claimed responsibility for most of the violence, and some political parties have decided not to hold rallies outdoors because of the risk.
On April 28, Taliban bombs targeting politicians in northwestern Pakistan killed 11 people.
The heightened violence has killed at least 60 people in recent weeks, with many of the attacks directed at candidates from secular parties opposed to the Taliban.
Representatives of at least one of those secular parties on April 28 reiterated his party's resolve not to allow such attacks to prompt an election boycott.