A series of bombings have killed 115 people across Pakistan, including 81 who died in twin blasts on a bustling billiards hall in a Shia area of the southwestern city of Quetta.
Pakistan's minority Shia Muslims have increasingly been targeted by radical Sunnis who consider them heretics.
A militant Sunni group claimed responsibility for today's deadliest attack, sending a suicide bomber into the packed pool hall and then detonating a car bomb five minutes later.
It was one of the deadliest days in recent years for a country that is no stranger to violence from radical Islamists, militant separatists and criminal gangs.
Violence has been especially intense in southwest Baluchistan province, where Quetta is the capital and the country's largest concentration of Shias live.
Many are ethnic Hazara who migrated from neighbouring Afghanistan.
The billiards hall targeted was located in an area dominated by the minority sect.
In addition to the 81 dead, more than 120 people were wounded in the double bombing, said police officer Zubair Mehmood.
The dead included police officers, journalists and rescue workers who responded to the initial explosion.
Ghulam Abbas, a Shia who lives about 150m from the billiards hall, said he was at home with his family when the first blast occurred.
He was trying to decide whether to head to the scene when the second bomb went off.
Hospitals and a local mortuary were overwhelmed as the dead and wounded arrived throughout the evening.
Weeping relatives gathered outside the emergency room at Quetta's Civil Hospital.
Inside the morgue, bodies were laid out on the floor.
The bombs severely damaged the three-storey building where the pool hall was located and set it on fire.
It also damaged nearby shops, homes and offices.
Lashkar-e-Jhangvi, a Sunni militant group with strong ties to the Pakistani Taliban, claimed responsibility for the attack.
Human Rights Watch sharply criticised the Pakistani government for not doing enough to crack down on the killings and protect the country's vulnerable Shia community.
It said more than 400 Shias were killed in targeted attacks in Pakistan in 2012, including over 120 in Baluchistan.
Pakistan's intelligence agencies helped nurture Sunni militant groups like Lashkar-e-Jhangvi in the 1980s, to counter a perceived threat from neighboring Iran, which is mostly Shia.
Pakistan banned Lashkar-e-Jhangvi in 2001, but the group continues to operate fairly freely.
Earlier, a bomb targeting paramilitary soldiers in a commercial area in Quetta killed 12 people and wounded more than 40 others.
The bomb was concealed in a bag and placed near a vehicle carrying paramilitary soldiers, said Akbar Hussain Durrani, the provincial interior secretary.
The bag was spotted by a local resident, but before the soldiers could react, it was detonated by remote control.
The United Baluch Army, a separatist group, claimed responsibility for the attack in calls to local journalists.
Pakistan has faced a violent insurgency in Baluchistan for years from nationalists who demand greater autonomy and a larger share of the country's natural resources.
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.
No group claimed responsibility for that attack, but suspicion fell on the Pakistani Taliban, which has waged a bloody insurgency against the government in the Swat Valley, where Mingora is located, and other parts of the northwest.
Meanwhile, a US missile strike in the northwest tribal region today killed five suspected militants in the seventh such attack in two weeks, Pakistani intelligence officials said.
The recent spate of strikes has been one of the most intense in the past two years, a period in which political tensions between the US and Pakistan led to a reduced number of attacks compared to 2010, when they were at their most frequent.
It is unclear whether the current increase has been caused by particularly valuable intelligence obtained by the CIA, or whether the warming of relations between the two countries has made strikes less sensitive.
Protests by the government and Islamic hard-liners have been noticeably muted.
The strike today occurred in a village near Mir Ali, one of the main towns in the North Waziristan tribal area, said Pakistani intelligence officials, speaking on condition of anonymity because they were not authorised to talk to the media.