PESHAWAR, Pakistan — A car bomb exploded outside a crowded market in northwestern Pakistan on Tuesday, killing at least 24 people in the latest attack by suspected militants apparently aimed at avenging an army offensive along the Afghan border.

The bombing, aimed at causing maximum civilian casualties, was the third blast in as many days in or close to Peshawar, the capital of the North West Frontier Province, an area bordering the tribal region where the army is pushing into a key Taliban and al Qaeda sanctuary.

The blast in Charsadda, some 40 kilometres north of Peshawar, was caused by some 40 kilograms of explosives stuffed into a van, said the senior police chief in Peshawar, Liaqat Ali Khan. Authorities were investigating whether the attack, which killed at least 24 people and wounded 102 others, was carried out by a suicide bomber, he said.

Rashid Kaka said he was returning from the mosque to his shop in the market when the bomb exploded, destroying stores on both sides of the road and knocking down electrical wires.

"It was deafening and there were clouds of dust all around. I could not see anything around me," said Kaka. "Later I saw many bodies lying scattered."

Foreign Minister Shah Mahmood Qureshi condemned the attack, calling those behind it the "enemies of Islam.

No one claimed responsibility, but authorities have blamed similar attacks in recent weeks on the Taliban.

The insurgents apparently hope the blasts will weaken the resolve of the army, which launched an offensive in mid-October against militants in South Waziristan, the main Taliban and al Qaeda sanctuary in Pakistan's tribal area along the Afghan border.

On Monday, a suicide bomber in a rickshaw detonated his explosives near a group of policemen in Peshawar, killing three people. A day before, a suicide bomber blew himself up in a market south of Peshawar, killing 12 people, including a mayor who once supported but had turned against the Taliban.

Less than two weeks ago, a car bomb killed 112 people in a market in Peshawar, the deadliest attack in Pakistan in more than two years.

The government has pledged to press ahead with the offensive despite the assaults. The U.S. supports the South Waziristan operation because Pakistan's tribal belt is home to many militants involved in attacks on Western troops across the border in Afghanistan.

Mian Iftikhar Hussain, information minister for North West Frontier Province, said Tuesday's bombing was evidence the government crackdown was putting pressure on the militants.

"They are not able to target freely, and that's why they are targeting innocent people," said Hussain. "But we and the people of Pakistan are determined to continue this jihad against terrorists undeterred."

Pakistan's army has pitted some 30,000 troops against up to 8,000 militants in South Waziristan, including many Uzbeks and other foreign insurgents who have long taken refuge in the lawless tribal areas.

The soldiers have been battling militants in three key Taliban bases in South Waziristan over the past few days.

The latest fighting has killed nine militants, an army statement said Tuesday.

The information is nearly impossible to verify independently since Pakistan has blocked access to the battle zone.