A suspected suicide bomber has wounded two policemen and killed himself in the Peshawar, the capital of Pakistan's North West Frontier Province (NWFP).
The aftermath of the deadly blast in Peshawar on 20 October
There have been a number of bomb attacks in Peshawar recently - one left six people dead.
Forty-two soldiers were killed in a suicide attack in the town of Dargai in NWFP last week.
Meanwhile, in Lahore 14 people were injured by a bomb left in a litter bin close to a bus stop, police say.
Peshawar police say the man who carried out Friday's suicide attack on a police patrol died on the spot.
They said the attacker was a local man, 20-year-old Nadeem Khan.
His father later identified the body.
Senior Superintendent of Police Iftikhar Khan told the BBC that the bomber was an illiterate man who had been working as an electrician.
He said Nadeem Khan used to spend most of his nights at a local mosque and would return home for breakfast.
The motive for the attack is not clear.
A bomb in a crowded market in Peshawar near the headquarters of Pakistan's border security forces on 20 October killed six people. It was the most serious in a number of unexplained explosions in Peshawar.
Last week North West Frontier Province was the scene of the deadliest attack by militants on the army since it began operations against pro-Taleban and al-Qaeda fighters close to the Afghan border.
A suicide bomber entered an army training school in the town of Dargai and killed blew himself up, killing 42 soldiers in the process.
The government said it had been expecting such an attack after the army said it had killed 80 militants in an aerial attack on a religious school (madrassa) in the neighbouring Bajaur tribal agency.
Local people said the dead were all innocent civilians that the attack had been carried out by US forces based in Afghanistan.