In addition to the fatalities, the suicide attack in Dera Ismail Khan left 13 people wounded.
Police later said that two assailants from the Peshawar market bombings had been killed and two suspects detained.
"Two terrorists have been killed but the operation is continuing. We are carrying out searches as others could be hiding," Sifwat Ghayyur, the city police chief, said.
Al Jazeera's Mike Hanna, reporting from Islamabad, said it appeared the series of bomb blasts were "inextricably linked".
"Certainly that is the way Pakistan's intelligence services are seeing it - investigating this wave of bombings that is happening in recent days," he said.
The attacks happened on a day Islamabad offered a cash reward for the arrest of Maulana Fazlullah, a religious leader said to be behind the Pakistani Taliban's campaign in another part of NWFP - Swat valley.
While a bounty of $62,000 was announced for Fazullah's capture, the government also pledged varying rewards to all those who help in tracking down 20 other Taliban leaders.
The government list included Muslim Khan, the Swat Taliban spokesman.
"People providing authentic information leading to the capture - dead or alive - of these individuals will receive a cash reward," said an announcement published in leading newspapers, along with mugshots of those wanted.
Pakistan's military has intensified its campaign against the Taliban in Swat in recent weeks.
But the fighters have hit back elsewhere.
A suicide attack in Lahore, in the eastern province of Punjab, killed at least 30 people and injured over 200 others on Wednesday.
The bombing flattened a police building and damaged offices belonging to the Inter-Services Intelligence (ISI), Pakistan's spy agency.
The Pakistani Taliban claimed responsibility on Thursday for the attack.
Hakimullah Mehsud, a deputy to Baitullah Mehsud, the Pakistani Taliban chief, told the Associated Press news agency in a telephone call that the suicide attack "was in response to the Swat operation where innocent people have been killed".
A group calling itself Tehrik-i-Taliban Punjab had earlier claimed responsibility for the bombing in a Turkish-language message posted on a Turkish website.
The group said the attack was related to the fight in Swat, according to the SITE group, which monitors such websites.
The attack was the third in recent months on Lahore, Pakistan's second-largest city, which sits well away from the Afghan border region where the Taliban has established strongholds.
Ayaz Amir, a columnist at The News, a Pakistani newspaper, told Al Jazeera: "I think most people realise this is not going to be a short war. Pakistan and the army are in it for the long haul.
"Even ordinary people on the street realise it as well and if they needed any more evidence, they could look to the large number of refugees who have come from different areas. People also realise how bad the situation is. I mean, what is the alternative? There are none."