Naseer Ahmed / Reuters
A paramilitary soldier reacts as he asks civilian to leave the scene of a bomb explosion in Quetta on Thursday.
Updated 7 p.m. ET: The death toll from twin bombings on a billiards hall Thursday in southwest Pakistan rose to 81, with at least 120 more injured, according to a senior police official.
Police officer Hamid Shakeel said the bombs went off about 10 minutes apart, The Associated Press reported, with the second blast causing the building to collapse. Several nearby shops, homes and offices were also damaged.
Lashkar e Jhangvi, a Sunni Muslim militant organization aligned with al-Qaida, took responsibility for the attack.
Many of the dead and wounded were Shiite Muslims, officials said; police officers, journalists and rescue workers who responded to the initial explosion were also among the dead, the AP reported.
The Associated Press interviewed Ghulam Abbas, a Shiite who lives some 150 yards from the pool hall. He said he was at home with his family during the first blast, and was thinking about going to the scene when the second bomb went off.
"The second blast was a deafening one, and I fell down," he told the AP. "I could hear cries and minutes later I saw ambulances taking the injured to the hospital."
The pool hall assault in Quetta, the capital of Baluchistan province, was the third terrorist attack of the day in Pakistan.
Earlier, a bomb targeting paramilitary soldiers in a commercial area in Quetta killed 12 people and wounded more than 40 others, Shakeel said, the AP reported.
Elsewhere in Pakistan, a bomb in a crowded Sunni mosque in the northwest city of Mingora killed 22 people and wounded more than 70, said senior police officer Akhtar Hayyat, the AP reported.
It was one of the country's deadliest days in recent years.
The Pakistani government's failure to crack down on the killings of the country's Shiite were criticized by Human Rights Watch, which said more than 400 Shiites were killed in targeted attacks in Pakistan in 2012.
"2012 was the bloodiest year for Pakistan's Shia community in living memory and if this latest attack is any indication, 2013 has started on an even more dismal note," Ali Dayan Hasan, Pakistan director at Human Rights Watch, told the AP.
"As Shia community members continue to be slaughtered in cold blood, the callousness and indifference of authorities offers a damning indictment of the state, its military and security agencies," Hasan said. "Pakistan's tolerance for religious extremists is not just destroying lives and alienating entire communities, it is destroying Pakistani society across the board."