At least 15 people were killed and 45 injured on Tuesday when a suicide bomber blew himself up in Islamabad near an enclosure of former prime minister Benazir Bhutto-led Pakistan People's Party at a meeting of lawyers due to be addressed by suspended Chief Justice Iftikar M Chaudhry.

The Chief Commissioner of Police in Islamabad, Khalid Pervez told the media that it was a suicide bomb attack and it took place 100 metres outside the venue where a number of political parties had set up their booths to welcome Chaudhry.

He said the attack left 13 dead and 45 wounded. TV channels, however, put the number of injured at around 100.

The blast took place at around 2030 hours Pakistan time when Chaudhry was being brought in a procession to the District Bar Association meeting venue.

His convoy was 20 minutes away from the spot when the explosion occurred. He was immediately driven to safety.

It appeared that bomber, whose severed head was found close to the site of the explosion at busy F-8 area of the city, was aiming to cause maximum casualties to PPP.

It was suspected that the PPP was made a target because Bhutto, who lives in self-exile abroad, was the only opposition leader to have welcomed the July 11 military crackdown on Lal Masjid in which 103 people, including radical cleric Abdul Rashid Ghazi, were killed.

Bhutto had said the operation in Lal Masjid should have been conducted much earlier but at the same time expressed her support to President Pervez Musharraf [Images] for carrying out the raid.

Immediately after the attack, the site resembled a war zone with blood-splattered clothes, splinters and other debris strewn around and several motionless bodies lying.

The injured, with their limbs and clothes soaked in blood, were transported by ambulances and other modes of transport to nearest hospitals.

The blast comes three days before Pakistan's Supreme Court is expected to decide whether to allow or overturn the March 9 suspension of Chaudhry by the President.

Ever since Chaudhry was suspended, almost all opposition parties have been welcoming him at his rallies across the country by setting up their own booths.

PPP had set up its enclosure close to Tuesday's venue to welcome him.

Some local activists of the party have been killed or injured in the blast, reports said.

However, it is not yet clear whether tonight's blast was directly connected to Lal Masjid military operation.

After the crackdown, a spate of suicide bomb attacks rocked several tribal areas targeting Pakistani military convoys and installations in which over 60 people, majority of them army personnel, were killed.

Some of the injured were stated to be activists of the Pakistan Muslim League, headed by exiled former prime minister Nawaz Sharif.

The police commissioner said the male suicide bomber was seen coming towards the venue and he blew himself up close to it. Five policemen were among the injured, Pervez said.

After initially being driven to safety, Chaudhry, who has emerged as a major rallying figure for the opposition parties to mount an agitation against Musharraf, however decided against going home and came to the venue despite advice by the officials to the contrary.

He arrived at the meeting along with his team of defence lawyers headed by Atezaz Ahesan, who is also a veteran Parliamentarian.

Interior Secretary Sayed Kamal Shah said elaborate security arrangements were made inside the venue, which included body scanners. There was very little that could be done as the blast took place outside, he said.

After the blast, several lawyers blamed the government, alleging that it was an attempt to scuttle the meeting.

PPP spokesman Faratullah Babar told PTI that 11 party activists have been killed and 37 injured in the attack.

"Most of the dead and injured are from our party. Those injured included local activists Israr Shah, who lost both the legs, and Nargis [Images] Mallik," Babar, who was at one of the hospitals treating the wounded, said.

PPP information secretary Sherry Rehman, who is currently in London [Images] attending the parliamentary party meeting of the PPP presided by Bhutto herself, said the explosion took place at the camp which was the largest and when local leaders were addressing the meeting.

Rehman said Bhutto and the party condemned the blast.

"PPP is paying the highest price for waging struggle for democracy and nobody can question its commitment. It is most unfortunate that the government is unable to provide security to political parties who have right to express their views," she said.

She also accused the government of allowing an 'atmosphere of uncertainty' to be built up that too when the country headed for general elections later this year.

Former ISI Chief Gen (retd) Hamid Gul, who was present at the venue when explosion took place, said it as an attack aimed at Chaudhry.

Gul, who was a supporter of the Islamist alliance Muthahida Majlis-e-Amal, said the explosion was apparently caused by a remote-controlled device.

Asked by private Geo TV how he could say it was directed against Chaudhry when he was nowhere near arriving at the venue, Gul said the blast appeared to have aimed at disrupting Chaudhry's meeting.

This is the second time that Chaudhry's meeting saw violence.

On May 12, 42 people were killed in Karachi in clashes between activists of the ruling ally Muthahida Quami Movement and the opposition parties when the suspended top judge had gone there to address a lawyers' convention. Chaudhry had to call off his visit.

Chaudhry has travelled to almost all parts of the country where he got unprecedented welcome. He also galvanised the opposition parties movement against Musharraf and posed the biggest political challenge to Musharraf's eight-year rule.

Lawyers have called nationwide strike on Wednesday to condemn the blast.

Musharraf has condemned the blast 'in the strongest terms', saying that it was a terrorist act.

The President expressed heartfelt condolences to the bereaved families whose kin had lost their lives in this 'dastardly act', an official annoucement said.

He directed the concerned authorities to provide best possible medical treatment to the injured and immediately inquire into the matter.

Musharraf also appealed to the public to remain calm, vigilant and assist the authorities in unearthing the culprits and bringing them to justice, it said.