A suicide bomber has killed at least 19 people and wounded many others in northwestern Pakistan. Such attacks have increased in the country, in recent weeks, and have killed scores of people since the military launched an anti-Taliban offensive in October to uproot terrorist bases in the South Waziristan tribal region, near the Afghan border. 

The target of the latest attack was a courthouse in the violence-hit city, Peshawar. Witnesses say the powerful explosion occurred during rush hour.  Several security personnel and lawyers are among the victims.  Doctors say some of those injured are in critical condition. Senior police officer Sahibzada Anis gave details of the incident, while talking to reporters at the scene.

The police officer says that the suicide bomber was on foot and detonated the device when security guards stopped him for a search at the main entrance.  The blast damaged several cars parked nearby.

Taliban insurgents have intensified attacks in the country - particularly in and around Peshawar - after the Pakistani army launched an offensive against militant bases in South Waziristan.  Officials say that, since early last month, more than 300 people have died in bombings and militant raids on government, civilian and Western targets in the country.

Speaking to reporters in Islamabad, Prime Minister Yousuf Raza Gilani condemned the suicide blast.  He says most of the militants commanders are either killed or on the run.

The prime minister warned that fleeing militants are using  weapons they have scattered around the country to carry out terrorist attacks in cities.  The Pakistani leader reiterated his position that Pakistan needs international help to enhance capacity of the law enforcement agencies to discourage the violence.

"We have the ability, we have the will [and] we have the resolve to fight against terrorism, [but] we lack capacity," Gilani said.

Pakistani military officials say their forces have killed more than 500 Taliban insurgents and have lost at least 70 soldiers, in the ongoing offensive in South Waziristan that began on October 17. 

Thursday's suicide attack in Peshawar took place hours after missiles fired by a suspected American drone killed at least four suspected militants and wounded five others the North Waziristan region, on the Afghan border. The area is a known stronghold of Afghan and al-Qaida militants.