The Sunni militant group Lashkar-e-Jhangvi claimed responsibility for the latest carnage, which set off demonstrations across the country.
The Hazaras are predominately Shiite Muslims who for a century have migrated eastward from the Afghan mountains, and have suffered targeted killings, suicide attacks and economic boycotts for more than a decade in the Quetta region. Some consider them foreign agents or heretics because of their easily recognizable dark Mongol features and Farsi dialect.
Early last year, 155 Hazaras were killed in two suicide attacks.
"Nearly 800 [Hazaras] have been killed since 1999 in targeted killing, suicide attacks, bomb explosions, drive-by shooting, lynching and assassinations," Quetta police official Abdul Razzaque Cheema told UPI Next.
Balochistan's chief minister, Abdul Malik Baloch, said the recent attack shattered the superficial calm.
Violence forced Hazara shopkeeper Abdul Ali to close his clothing store in the city's sprawling Liaqaat Bazaar in 2010 when he faced the risk of a targeted killing. He opened another store but that was destroyed last year in a blast that was yet another attack on the Hazaras.
"It is difficult to make ends meet now and we are very hard-pressed financially," Ali told UPI Next.
Historically persecuted in Afghanistan and Pakistan, the current round of anti-Hazara violence started in 1990 because of creeping fundamentalism and the emergence of the Taliban, Mohsin Changezi, an ethnic Hazara, Urdu poet and Quetta school teacher, said. Now, he told UPI Next, "The violence is so deep and pervasive that we are confined to certain suburbs. It is dangerous to venture out of these localities and one can do so on the risk of being killed or maimed."
About 550,000 of the country's 800,000 Hazara now live in and around Quetta, a city of 2.8 million, Abdul Wahab, a recently retired joint census commissioner, told UPI Next.
Hussain Naqi, national coordinator at the non-governmental Human Rights Commission of Pakistan, said extremists target Hazaras because "they consider them heretics and foreign agents in addition to working against the interests of the country."
Abdul Hasan, a Hazara and the former chairman of the Persian Department at the University of Balochistan, said he has stopped going to the campus after receiving threatening calls and messages.
"I feel very frustrated by sitting idle but have no choice but to wait for things to get better," he told UPI Next.
Hazaras have responded to the violence by clustering in two Quetta suburbs, informally known as Hazara Towns, whose nearly 100 percent Hazara populations are crammed in a ghetto-like existence.
Many Hazaras, particularly the young, have been leaving Balochistan for their safety.
Rukhsana Najfi, a middle-age widow whose engineer husband was killed in a 2011 attack, said she is desperately lonely now that her children have fled the region to escape a similar fate.
"My life has been turned topsy-turvy after his death and now I live by myself in Quetta with memories of good old days because now my kids are living in different towns and countries," she said.
Historian Mubarak Ali told UPI Next the Hazara have been fleeing persecution for more than a century.
"They had fled Afghanistan to avoid massacre during the reign of Amir Abdul Rehman, from 1880 to 1901, and started migrating to the then-British India and came in droves to Quetta, the upcoming garrison town developed by the colonial power to monitor the western frontiers," he said.
Ali Dayan Hasan, the director of Human Rights Watch in Pakistan, said in a recent interview that "the Hazaras are being killed not because they are party to a conflict but because they are helpless targets."
"Deadly attacks on Shia communities across Pakistan are escalating," Brad Adams, the group's Asia director, said in a 2012 statement. "The government's persistent failure to apprehend attackers or prosecute the extremist groups organizing the attacks suggests that it is indifferent to this carnage."
Naqi told UPI Next nearly all the terrorist activities against Hazaras have been claimed by Lashkar-e-Jhangvi "but there are no serious attempts to arrest and imprison various militants."
"Some known terrorists have escaped from the high-security prison and are again active in killing the defenseless community," he said.
Shah Mohammad Mari, a Baloch historian and writer in Quetta, cited other significant factors that are responsible for the escalating violence.
"The sectarian sentiment has been promoted as a deliberate policy to divide society along those lines," he told UPI Next.
Mari also said the Hazara killings have been used to divert attention from the current Baloch insurgency by the military and civil establishment, and hide related vital issues and the prevailing sense of insecurity and discontent.
The provincial government says it is trying to protect Hazara citizens by cracking down on militancy and strongly refuted the charge that the recently elected coalition government is not taking any action, as was the case with the previous government.
Ishaque Baloch, the central vice president of the Balochistan National Party and spokesman for the province's coalition government, told UPI Next: "As a secular and progressive party, our first priority is to promote religious tolerance and diversity, and we ask clergy to help us in fostering unity. We are fighting the mindset that promotes religious intolerance which was encouraged as a policy during the dictatorial regimes."
Abdul Khaliq, chairman of the Hazara Democratic Party, told UPI Next from Quetta, "In order to restore peace and give security to the beleaguered community, it is imperative to make fool-proof security arrangements and, more importantly, try the perpetrators by the due process of law."
These steps will go a long way to instill confidence in Hazaras and give them an opportunity to live peaceful lives, he said.
The provincial government agrees.
"In principle, we agree to all these demands, and believe that law and order will be improved with our latest measures and the Hazara community will live in peace," Ishaque Baloch said.