( dpa ) - A suicide bomber struck Thursday outside the High Court building in the eastern Pakistani city of Lahore just before an anti-government rally, killing at least 20 people including 19 policemen, a senior police official said.
The death toll was expected to rise, with up to 51 people injured in the attack, including at least 15 policemen who were in critical condition at three local hospitals.
The bomber, apparently riding a motorcycle, forced his way through street barricades outside the court building at 11:45 am, where dozens of riot police had gathered ahead of a scheduled rally by local lawyers.
"It seems that a suicide bomber riding a motorbike rammed his bike into a police van," Aftab Ahmed Cheema, senor superintendent of police in Lahore, told Deutsche Presse-Agentur dpa.
He said there were police officers inside and outside the police van, as well as standing on the street nearby. He said that 19 policemen and one civilian were confirmed killed and 51 people wounded.
Dr Ehsan Elahi, an emergency room officer at the Lahore's Mayo Hospital, the closest to the blast site, told dpa that the bodies of 19 policemen and one civilian were taken there.
"We also have 36 injured, most of them policemen," he said.
Local television stations, citing various police and medical sources at the three hospitals, said 21 policemen were killed.
Malik Iqbal, chief of police in Lahore, told local stations that police were the target of the attack, but said the bomber was on foot.
Video footage showed bloody police caps, shoes, riot shields, helmets and sticks lying in the street, damaged vehicles, and a dead horse that had been connected to a carriage likely passing at the time of the blast.
Police were seen closely examining a partially destroyed motorcycle lying in the street, possibly belonging to the bomber.
Ambulances and other emergency vehicles rushed victims to three local hospitals in Lahore, 288 kilometres south-east of Islamabad.
The lawyers preparing to participate in the protest against the sacking of Supreme Court and High Court judges last November by Pakistani President Pervez Musharraf, were attending a meeting inside the building of the local bar association when the attack happened.
It was not the first time that a suicide bomber had targeted police. During a siege against Islamic militants holed up inside Islamabad's Red Mosque in July 2007, a bomber walked up to a group of policemen eating lunch at a small roadside restaurant and blew himself up, killing eight of them as well as five civilians