12 November 2010 Last updated at 09:15 ET

Karachi holds police building attack funerals

Thursday's bomb blew away much of the police building

Funerals have been held for eight policemen killed in an attack on anti-terrorist police headquarters in the southern Pakistani city of Karachi.

Thursday's bombing devastated the building, leaving at least 20 dead and 100 injured.

Many schools and offices are closed and there is little traffic on the roads.

The Taliban claimed the bombing. Officials believe they were trying to free militants they thought were detained there.

Up to five people are still missing and feared buried in the debris, officials say.

It was the biggest blast ever to hit Pakistan's commercial capital, involving 1,000kg of explosives, the authorities said.

Sindh Home Minister Zulfiqar Mirza told reporters the attack was on the scale of the Islamabad Marriot Hotel bombing of 2008 in which scores of people were killed.

In recent years the Pakistani Taliban have been behind a number of similar attacks on high-profile targets, including police and army compounds.

'Biggest blast'

The truck, laden with explosives, exploded after slamming into the Criminal Investigation Department building on Thursday night.

Detectives are collecting footage from CCTV cameras installed at several points along the high-security zone where the office was located.

They are looking to determine the route the explosive-laden trick took to approach the building without being checked by security personnel.

The blast took place in the busy evening rush hour

The site of the blast is not far from the Sindh province chief minister's residence, the US consulate and several five-star hotels, including the Sheraton.

The policemen killed in the attack were given funerals with full honours at police headquarters in the Garden area of southern Karachi. Senior government and police officials attended, amid tight security.

The bodies of paramilitary soldiers who also died have been sent to their home towns and villages, mostly in the north-west of the country.

The Karachi attack came a week after a suicide bombing on a mosque packed with worshippers killed 68 people in the north-west.

Last month, 25 people were killed in a blast at a shrine in Punjab province. Another attack at a Karachi shrine two weeks earlier killed nine and was claimed by the Taliban.

On 3 September, an attack on a Shia Muslim rally in Quetta killed at least 50 people.

Until late December 2009, Karachi had escaped much of the violence which came after Pakistan's security forces cracked down on Taliban and al-Qaeda militants in the north-west.