A deafening blast ripped through scores of mourners in a Quetta hospital on Monday killing 63 people, mainly lawyers, in this year's bloodiest terror attack in Pakistan, officials said.
Balochistan Health Minister Rehmat Baloch blamed a suicide bomber for the carnage that took place when a large number of lawyers had gathered at the Civil Hospital with the body of a lawyer shot dead hours earlier.
The hospital superintendent confirmed the toll, ARY News channel reported.
Two legs of a body found at the site were likely to be that of the suicide bomber, it said.
Balochistan Chief Minister Sanaullah Zehri blamed the Indian intelligence agency RAW, saying it was responsible for incidents of terror in Quetta.
His comments about the RAW came even before the police could say who was responsible for the horrific attack.
The massive explosion occurred when nearly 100 lawyers and some journalists reached the Civil Hospital with the body of Bilal Anwar Kasi, president of the Balochistan Bar Association who was killed earlier.
Police officer Zahoor Ahmed Afridi said most of the dead were lawyers. Several lawyers, including Baz Mohammad Kakar, the former president of the Balochistan Bar Association, were injured, Dawn reported.
Gunfire was heard shortly after the explosion. Shahzad Khan, a cameraman with Aaj TV, was also killed in the explosion while the cameraman for Dawn News was severely injured, Dawn said.
A stampede broke out after the bombing, causing chaos at the hospital, witnesses said. Smoke filled the corridors of the emergency ward. Video footage showed lawyers rushing with stretchers to help the wounded.
Samaa TV said bodies were strewn on the floor, some still smoking, "amid pools of blood and shattered glass".
Shocked and dozed survivors wept and comforted one another, journalists at the site said. Many of the dead wore black suits and ties.
Officials said as jammers were activated immediately after the blast, it became difficult to contact officials at the site.
Police surrounded the hospital and an emergency was declared in all Quetta hospitals. Senior military officers also rushed to the hospital.
"This was a security lapse and I am having this personally investigated," Balochistan Home Minister Sarfaraz Bugti said.
Prime Minister Nawaz Sharif, who left Islamabad for Quetta, condemned the killings and expressed his "deep grief and anguish over the loss of precious human lives".
"No one will be allowed to disturb the peace in the province that has been restored thanks to the countless sacrifices by the security forces, police and the people of Balochistan," he said in a statement.
Former Chief Minister Abdul Malik called it the "blackest day" in the history of Balochistan.
It was the worst terrorist attack in Pakistan this year since the March 27 bombing at Gulshan-e-Iqbal park in Lahore that left 75 people dead.
Lawyers have been targeted several times in recent months in Balochistan.
One lawyer, Jahanzeb Alvi, was shot dead on August 3. Bilal Kasi, who himself was shot dead on Monday, had condemned Alvi's murder and announced a two-day boycott of courts.
The principal of University of Balochistan's law college, Barrister Amanullah Achakzai, was also shot dead by unknown assailants in June.
Balochistan has experienced violence and targeted killings for more than a decade.
Pakistan's largest province by area, Balochistan is home to a low-level insurgency by Baloch separatists. Al Qaeda-linked and sectarian militants also operate in the region.
Balochistan Home Minister Sarfaraz Bugti said over 30 killed in the bombing. "This was a security lapse and I am having this personally investigated," he said.
Police said unknown men also opened fire after the blast.
Panic tore through the hospital after the incident and emergency has been declared at hospitals in Quetta.
A heavy contingent of Frontier Corps and police arrived and cordoned off the area.
It is suspected that the attack was carried out by a suicide bomber, Bugti told DawnNews.
Two unidentified men opened fire at Advocate Kasi's car near Quetta's Mengal Chowk on Manno Jan road as he left his home in the morning for work, police officials said. The former president was shifted to Civil Hospital, where he succumbed to injuries.
There were no immediate claims of responsibility for the blast or the earlier shooting.
The provincial capital bordering Iran and Afghanistan has been at the receiving end of several such acts of terror. In May, two persons were killed and five injured when an explosion occurred at the main entrance of Balochistan University.