PESHAWAR: A suicide bomber on Monday blew up a car packed with explosives near a college in Pakistan's Peshawar, killing four people in the latest attack on a city beset by Taliban-linked violence.

The bomber struck in a suburban road as children were going to school in the northwest city, devastating a mosque, destroying two rooms at a boys' college and bringing down one wall of a police station, witnesses said.

It was the fifth suicide attack in eight days to hit the sprawling city of 2.5 million people, which lies on the edge of Pakistan's lawless tribal belt, where US officials say Al-Qaeda are plotting attacks on the West.

Attacks in the northwest have soared as 30,000 Pakistani troops press into Taliban strongholds in the hostile terrain near the border withAfghanistan where 100,000 NATO and US troops are fighting against a deadly insurgency.

"The death toll is four and there are 26 injured," doctor Zafar Iqbal at the Lady Reading hospital told AFP. One child was among the dead with four wounded.

Witnesses said that a pick-up vehicle sped towards the police station and exploded nearby, leaving much of the building in ruins as ambulances raced through the streets in the densely populated suburb of Budh Ber.

Teacher Mohammad Shahid said he just dropped off his children at school when he heard a deafening blast, which left a five feet deep and nine feet wide crater (one metre by two metres) in the ground.

"I looked back and saw parts of a vehicle flung in the air and then the body of my neighbour fell on the ground near me. It was a horrible sight," he said.

Javed Khan, who drives a horse cart, said the car sped towards him forcing him to leap out of its path, before the explosion hit.

"I fell on the ground, shrapnel hit my forehead. I saw debris all around and people crying for help," Khan said.

Senior police official Khursheed Khan confirmed it was a suicide attack.

Pakistan's security forces are on the frontline of a deadly Al-Qaeda-linked campaign that has killed more than 2,500 people in 28 months in the nuclear-armed Muslim country, recently increasing in frequency and intensity.

Although there was no immediate claim of responsibility, the homegrown Tehreek-e-Taliban Pakistan (TTP) has vowed to attack in the cities to avenge a military assault on its South Waziristan stronghold, now into a fifth week.

The TTP claimed responsibility for a suicide car bombing that killed 15 people in Peshawar on Saturday and the bombing of the Peshawar headquarters of the nation's top intelligence agency, the ISI, on Friday that killed 17 people.

Militant attacks, which have also started to inflict mass casualties on civilian targets such as market places, have killed more than 450 people -- most of them in Peshawar -- since early October.

Pakistan launched 30,000 troops into a three-pronged offensive into South Waziristan on October 17, an operation that has been strongly endorsed by the United States which aims to crush the TTP leadership and strongholds.

The military push followed a similar offensive earlier this year in the northwest Swat valley, which the army declared a success in July, although fighting continues in Swat and throughout the troubled region.

On Sunday, about 50 militants from the banned Lashkar-e-Islam extremist group stormed the home of Fahimuddin, a local mayor who had raised a militia to fight the Taliban, in Bazid Khel village on Peshawar's outskirts.

Karim Khan, a senior police official in Peshawar, said three militants were killed in the clash with Fahimuddin's militia. The rest fled the scene.

Lashkar-e-Islam (Army of Islam), which has loose ties to TTP movement, enforces prayers five times a day and punishes people accused of prostitution, gambling and other vices.