The full scale of the bomb damage was apparent on Wednesday
A three-day general strike is being held in the Pakistani town of Charsadda following a bombing on Tuesday which killed at least 32 people.
Officials now say the attack, which injured 70 others, was probably aimed at the head of police in the district.
He had just passed the intersection where the bomb went off.
Meanwhile the army says that it is in control of 80% of South Waziristan and that nine Taliban militants have been killed in the latest fighting there.
The BBC's Syed Shoaib Hasan in Islamabad says that there is a climate of fear in Charsadda following Tuesday's bombing, with market traders demanding better protection from the authorities.
The blast occurred as shoppers thronged the main market in the town, which lies north-east of Peshawar.
The attack was the third in as many days in North West Frontier Province (NWFP).
The strike was called by trade unions and market associations in Charsadda - the ideological centre of the secular Awami National Party (ANP), which is currently governing NWFP.
The town has been repeatedly struck by bomb and suicide attacks targeting ANP leaders.
Organisers say that the strike is to mourn lost lives and to protest against the lack of proper security measures to prevent such attacks.
Charsadda's main bazaar and roads remained largely deserted on Wednesday.
More than 300 people have been killed in a wave of attacks as Pakistani troops mount an assault against the Taliban in South Waziristan.
Police said about 40kg of explosives had been placed in a car which exploded outside the busy market. There was no immediate claim of responsibility.
Our correspondent says that ordinary citizens are increasingly being targeted in bomb attacks. Analysts believe this is because the militants are cornered and under great pressure by the military in South Waziristan.
Officials insist they are determined to complete the Waziristan offensive.
"We are fully committed and this is our resolve to eliminate terrorism completely," Prime Minister Yousuf Raza Gilani told reporters Wednesday in Islamabad.
"This is a challenge for us and we accept the challenge as this is the primary duty of the government to protect the life and property of the people."
Mr Gilani said that militants were waging a "guerrilla war" to avenge the military operation in South Waziristan.
"They are launching suicide attacks because our army has captured their strongholds" in the tribal region, he told parliament late on Tuesday.
The previous day a suicide bomber killed himself and at least three people near a police checkpoint in Peshawar. A day earlier at least 12 were killed in a suicide bomb attack near the city.