A bomb hidden between bags of potatoes at an outdoor Pakistani market killed at least 16 people on Friday, half of them ethnic Hazaras, officials said, in an attack apparently aimed at minority Shi'ite Muslims.
At least 30 people were wounded in the blast in the southwestern city of Quetta, capital of resource-rich Baluchistan province, officials said.
Baluchistan is the focus of the $57 billion China Pakistan Economic Corridor, a transport and energy link planned to run from western China to Pakistan's southern deepwater port of Gwadar.
The attack came after a lull in violence against the mainly Shi'ite Hazara minority in Baluchistan lasting at least a year, though there have been isolated shootings.
The blast took place at Hazar Ganji, a fruit and vegetable market on the outskirts of Quetta.
"I have confirmation of 16 martyrs - eight belong to the Hazara community, seven others who worked here, and one is from the Frontier Constabulary," a city police official, Abdul Razzaq Cheema, told reporters.
The explosive device was hidden between sacks of potatoes, he said.
No group immediately claimed responsibility.
Hazaras have been frequently targeted by Taliban and Islamic State militants and other Sunni Muslim militant groups in both Pakistan and Afghanistan. They have been heavily targeted in Afghanistan in attacks claimed by an affiliate of Islamic State.
Ethnic Baluch separatists are also fighting against what they call the unfair exploitation of their province's gas and other resources.
"This seems to have been sponsored from across the border," Baluchistan home minister Zia Langove told Reuters, referring to neighbouring Afghanistan. "It is aimed to disturb peace, which to a great extent, has been achieved in Baluchistan."
In 2013, three bombings killed more than 200 people in Hazara neighbourhoods, prompting security forces to escort Hazara buses to the market. The same practice was followed on Friday, but the blast took place in the market.
"Targeted for their religion by sectarian armed groups, (Hazaras) have suffered many such tragedies over several years. Each time there are promises that more will be done to protect them, and each time those promises have failed to materialise," Amnesty International's Deputy South Asia Director, Omar Waraich, said in a statement.
"Prime Minister Imran Khan's government has made important commitments to protect all religious groups in the country. Those commitments must translate now into policies to effectively protect the Hazaras of Quetta, ending more than a decade of bloodshed that has scarred their community.