Peshawar, May 25 (IANS) Four policemen were killed and 28 people injured when a suicide bomber rammed his vehicle packed with explosives into a police station in this Pakistani city early Wednesday.

Geo News reported that eight police officials were among the 28 people who were wounded in the powerful explosion.

The deafening blast was heard across the city and the police station building came crumbling down. Windowpanes of nearby buildings were shattered.

Xinhua reported that the blast took place at about 4.40 a.m at the police station on the University road.

Many people were buried under the debris.

The suicide attack at the police station comes just five days after at least one person was killed and 10 people, including two Americans, were injured in a powerful explosion that targeted US consulate vehicles here.

Pakistan Taliban and Al Qaeda have vowed to avenge the death of Osama bin Laden by threatening to launch attacks on the US and Pakistan. Osama was shot dead May 2 by US Navy SEALs who swooped into Abbottabad city onboard stealth helicopters and then stormed the Al Qaeda leader's high-walled hideout.

Barely 10 days later May 13, the Taliban viciously struck back with two suicide bombers blowing themselves up at a training centre in Charsadda for Pakistani security personnel, killing at least 80 people and injuring over 100.

On Sunday night, terrorists stormed a military base in Karachi. The 15-hour siege ended Monday afternoon with 14 people, including four terrorists, being killed.