At least 21 people, including entire families and children, were killed when a fire broke out in a residential building in a refugee camp in northern Gaza on Thursday, according to Palestinian authorities in Gaza.   

  The fire broke out in the Jabaliya refugee camp, Gaza’s interior ministry said.  The preliminary investigation found a large amount of gasoline inside the building, which contributed to the escalation of the fire, he added.   

  Everyone in the building was killed, ministry spokesman Iyad Al-Bazm said.   

  The dead include entire families, local media reported, citing a doctor, a local government official and a pharmacist, as well as their wives and children among the victims.   

  Hussein Al Sheikh, secretary general of the Palestine Liberation Organization (PLO) executive committee, called on Israel to open the Erez crossing to allow the wounded to be taken to hospitals outside Gaza.   

  Israeli Defense Minister Benny Gantz said it would be the right thing for Israel to do to save human lives, but there appeared to be no injured survivors to transport.   

  Israel controls the Erez crossing, one of the few checkpoints that allow traffic between Israel and Gaza.   

  Police forces, civil defense and forensic teams are still investigating the incident, Gaza’s interior ministry said.   

  Many families living in Gaza store petrol and diesel in electricity generators as the area only has electricity for eight hours a day as it only has one power station.   

  Hamas, the militant group that rules Gaza, expressed its sorrow over the deaths and called on the Palestinian people to attend the funerals of the victims on Friday.   

  Palestinian Authority President Mahmoud Abbas declared a day of mourning for the victims.