The explosion happened after officers signalled a suspect vehicle to stop at a checkpost in the Lakki Marwat district of Khyber Pakhtunkhwa, local police chief Gul Wali Khan told AFP.
The driver ignored the instruction so police opened fire and the bomber detonated his device, he said.
About 40 shops and 10 houses were damaged in the blast.
"We have recovered five bodies so far from the debris," he said. "The bomber detonated his car. It was a suicide car bomb attack.
The fatalities were all civilians killed when the buildings collapsed, the police chief said, adding that another 35 people were wounded, 10 of them police officials.
The two attacks took place as Pakistan celebrated Eid-ul-Fitr, which marks the end of the fasting month of Ramadan.
Lakki Marwat district borders South Waziristan, part of Pakistan's militant-infested semi-autonomous tribal belt near Afghanistan, which Washington calls the “most dangerous” place on Earth and a global headquarters of Al-Qaeda.
Earlier Thursday gunmen killed seven people, four from the same family, in an ambush on a vehicle in Kurram tribal district in a possible sectarian attack, officials said.
The vehicle, with eight people on board, all from the minority Shiite community, was attacked in the Makhizai area of lower Kurram, local administration chief Javedullah Khan told AFP.
"Gunmen hiding behind the bushes along the road opened fire," killing seven of those on board, he said, adding that the eighth person was injured.
A local security official confirmed the attack, but no-one immediately claimed responsibility and Khan said authorities had not ruled out the motive being a family vendetta.
Last week 11 people were killed when a remote-controlled bicycle bomb exploded at a busy hotel in Nowshera, northeast of Peshawar, the capital of Khyber Pakhtunkhwa.
Kurram has a history of clashes between majority Sunni Muslims and minority Shiites and a similar incident there in July left seven Shiites dead.
The northwest suffers from chronic insecurity largely connected to the tribal belt and two weeks ago, 51 people were killed by a suicide bomber in a crowded mosque in Khyber tribal district, Pakistan's deadliest attack for three months.
COMMENTS (10)
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@Ode Fine.You are against USA. Agreed. Then why kill your own people,your own countrymen,pious Muslims? Why when such incidence takes place Imran Khan,Maulvis and so called self declared custodians of Muslim faith keep their lips glued by the most super adhesive.I am sorry to say most Pakistanis have learnt the art of escapism.There are many sane,balanced people in Pakistan but they are out numbered.
A simple question to all those Imran Khan fanboys and burger bachhas: If the drones stop and NATO/US pullout of Afghanistan the only thing that will happen is that Taliban will enter Pakistani terroriteries and cross border attacks against security forces and inncoent civilians will only inc not decrease...
Imran Khan is right when he says that roots of extremism need to be taken care of and that if USA's imperialist actions were not taking place in AF-Pak, both the countries would have been far better. Imran Khan has talked a million times about the need for dialogue and alienating the terrorists from the civilian populations. This alienation can only be done if USA is not bossing around the AF-Pak region. Once USA is out, alienating the terrorists, targetting those you are not ready for stopping to use arms will be easier. If you are against dialogue and all for bombing the hell out of civilian populations which may or may not kill a non-convicted suspected terrorist and kill and maim and radicalize many innocent civilians, you should know that even the IRA problem was taken care of on the table of dialogue and negotiations.
@MY name is Khan: Actually I think Imran Khan is right. If we dont stop the drones, these killings will only continue because they are "retaliations." Please remember that b4 911, not a single event used to happen like this. We need to pull out of this madness.
frankensteins never help their creators.........pakistan should have realised this long back......
Not our war right? I'm sure if we just listened to Imran Khan and got USA to stop all the drone attacks this would all be over right? These are our strategic assets right?
Grow up Pakistan. Destroy the terrorists before they destroy our country.
It is simple, Zardari, you front for the American war and kill those in the FATA,and they will kill your police and Army and may be get you one of these days.They got BB, did not they? And she was thousand times better person than you ever was.
@Incredible: as well as the ostrich like "hindus, amriikis and zionists are responsible" rants......
Eid Mubarak to all my fellow citizens, not sure if even God can help our lovely Islamic Republic of Pakistan at this point.
The killing fields continues.