PESHAWAR, Pakistan (AP) -- A car bomb exploded in a crowded market in Pakistan's troubled northwest tribal region near the Afghan border Monday, killing 17 people and wounding more than 40 others, officials said.
The bomb went off near the women's waiting area of a bus stop close to the office of one of the Khyber tribal area's top political officials, said Hidayat Khan, a local government official. It was unclear if the office was the target, he added.
The 17 dead included five boys and two women, said Abdul Qudoos, a doctor at a local hospital in Jamrud town, where the attack occurred. At least 44 people were wounded, he said.
The explosives were packed in a small white car parked in the middle of the road, blocking traffic, said Shireen Afridi, who was nearby buying a phone card when the bomb exploded.
"There was fire in which children burned, women burned, poor Afghan people burned, and it caused a lot of destruction," said Afridi. "People's heads were lying in the drain."
Local TV footage showed several cars and shops in the market that were badly damaged. Residents threw buckets of water on burning vehicles as rescue workers transported the wounded to the hospital.
The market was located close to the office of the assistant political agent for Khyber, said Khan, who works in the office. Initial reports wrongly indicated the women's waiting area was for the political office, not the bus stop.
No group immediately claimed responsibility for the bombing.
Khyber is home to various Islamist militant groups, including the Pakistani Taliban, who have waged a bloody insurgency against the government for the past few years.
Also on Monday, Taliban militants fired rocket-propelled grenades and automatic weapons at an army convoy in northwest Khyber Pakhtunkhwa province, killing three soldiers and wounding three others, said Nisar Ahmad, a local government official.
The soldiers were escorting a polio vaccination team outside the town of Lakki Marwat when the attack occurred, said Wazir Khan, a local resident.
The Taliban have spoken out against polio vaccination in recent months, claiming the health workers are acting as spies for the U.S. and the vaccine itself causes harm.
A Pakistani Taliban spokesman in the South Waziristan tribal area, Asim Mehsud, claimed responsibility in a telephone call to The Associated Press.
"These polio drops are a deadly American campaign to poison us," he said.
In the southern city of Karachi, an unknown gunman shot and killed a Pakistani working with the World Health Organization's anti-polio campaign, said police officer Qamar Ahmed.
Zubair Mufty, who works for the U.N. agency, said it was looking into the reported attack.
The army has carried out offensives against the Taliban in most parts of the tribal region, including Khyber, but militants continue to carry out regular attacks in the country.
On Saturday night, 10 Taliban militants attacked the military side of an international airport in Peshawar with rockets and car bombs, killing four people and wounding over 40 others. Five of the militants were killed during the attack, and five others died the next day in a gunbattle with security forces.
Elsewhere on Monday, gunmen in the southwest killed a provincial government spokesman and two nearby policemen in an apparent sectarian attack, police said.
The attackers shot dead Khadim Hussain Noori in Quetta, the capital of Baluchistan province, said local police official Hamid Shakeel. Noori was the provincial spokesman and also a Shiite Muslim.
As the gunmen were speeding away on a motorcycle, they killed two policemen and wounded a third, said Shakeel.
Baluchistan has experienced a spike in sectarian killings in the past year as radical Sunni Muslims have targeted Shiites, who they consider heretics.
The province is also the scene of a decades-long insurgency by Baluch nationalists who demand greater autonomy and a larger share of the province's natural resources.
Associated Press writers Abdul Sattar in Quetta, Pakistan, Ishtiaq Mahsud in Dera Ismail Khan, Pakistan, and Adil Jawad in Karachi, Pakistan, contributed to this report.