Protests over the killing of 11 Shi'ite Hazara minority coal miners by Islamic State militants on Sunday have spread to other cities in Pakistan, including the economic powerhouse of Karachi.
Police said on Thursday there were sit-ins in at least 19 locations in the sprawling southern metropolis.
Flights were delayed because access to the airport had been affected.
Hundreds of Hazara have been killed in Pakistan over the last decade in attacks by Pakistani Sunni Muslim militant groups who see Shi'ites as apostates, and by Islamic State militants. Attacks have included bombings in schools and crowded markets and brazen ambushes of buses along Pakistani roads.
The protesters have asked Prime Minister Imran Khan to visit Quetta, where demonstrators have kept up a five-day long vigil alongside coffins carrying the victims' bodies, blocking a major highway.
Demands also include the dissolution of the provincial government there, and a serious effort by Islamabad to find and punish the culprits.
Most of the victims were seasonal migrant workers from an impoverished area of neighbouring Afghanistan.
Their gruesome killings, near the coal fields they worked, were filmed and later posted online by Islamic State.
The Afghanistan consulate in the city of Quetta said seven of the victims were Afghan, and asked Pakistani authorities to repatriate three of the bodies on Tuesday.
Khan has dispatched three cabinet ministers to persuade the protesters in Quetta to disperse, to no avail.
"I share your pain & have come to you before also to stand with you in your time of suffering," Khan tweeted on Wednesday.
"I will come again very soon to offer prayers and console with all the families personally."
Leaders of Pakistan's two largest opposition parties, Maryam Nawaz and Bilawal Bhutto Zardari, were scheduled to visit the Quetta sit-in on Thursday.
After nearly 100 Hazaras were killed in a 2013 bombing in Quetta, sit-ins were held across Pakistan that only ended after the then prime minister met with the mourners.