Amnesty urged Pakistani authorities to "immediately carry out an impartial and independent investigation into the persistent failure of civil and military authorities to end such attacks."
A lack of prosecutions
The rights group said that to its knowledge, "no one has been prosecuted for the January 2013 attacks or other targeted killings of Hazaras in recent years."
The bombing Saturday also drew condemnation from the office of U.N. Secretary-General Ban Ki-moon and the Human Rights Commission of Pakistan.
The commission said it was "at a loss for words at this latest catastrophe to befall the long-suffering Hazaras of Balochistan."
Lashkar-e-Jhangvi has tried to justify its attacks by arguing that according to its interpretation of Islam, Shiites are not Muslims. It claims Shiites insult close companions of the Islamic prophet, Mohammed.
But human rights groups are scathing in their criticism of the group.
"These attacks demonstrate Lashkar-e-Jhangvi's utter disregard for human rights and basic principles of humanity," Arradon said.