Doctors on Monday were working to save the lives of multiple people who were gravely injured in a devastating <a href="https://www.thenationalnews.com/tags/new-york-city/" target="_blank">New York City</a> apartment fire that left 17 dead, including eight children. Sunday's fire in the Bronx left dozens of people hospitalised. <a href="https://www.thenationalnews.com/world/2021/11/03/eric-adams-elected-mayor-of-new-york-city/" target="_blank">New York City Mayor Eric Adams</a> said on Monday that several people were still in critical condition. Mr Adams revised an earlier death toll that had put fatalities at 19. "We pray to God that they’ll be able to pull through," he told CNN. The mayor announced on Monday the city has started an investigation into the deadly fire and that the White House expressed both support and condolences in a call. "Just a few moments ago, I received a call from President Biden and he has made it clear that whatever we need, the White House is going to be there for us," Mr Adams said. "He has just sent a very strong message that this is on the radar of the entire globe." Mr Adams described the event as a "tragedy beyond measure" in a tweet on Sunday. Pope Francis offered his condolences on Monday to the victims of the "devastating" apartment fire. His message noted the loss of so many children, and said the pope “entrusts the victims and their families to the merciful love of Almighty God and invokes upon all consolation and strength in the Lord.” “This is a global tragedy because the Bronx in NYC is representative of the ethnicities and cultures across the globe, and so everyone is feeling the pain of what we are experiencing," Mr Adams said of international support. Investigators determined that a malfunctioning electric space heater, plugged in to give extra heat on a cold morning, started the fire in the 19-storey building. In a preliminary investigation, Mr Adams said the city had found two outstanding building violations, but that neither was related to insufficient heat that might prompt residents to rely on space heaters for warmth. He also said the investigation would focus on complaints from building residents that said smoke alarms went off frequently, leading some residents to stay in their units because they didn’t realise it was a real fire. About 200 firefighters responded to the scene on Sunday at the Twin Park apartment building on East 181st Street. Mr Adams said the firefighters continued their rescue efforts even after running out of their oxygen supply. “Their oxygen tanks were empty and they still pushed through the smoke,” he said. Photos online showed a rescue ladder extended up to an eighth-floor window. Most of the victims suffered from severe smoke inhalation, New York fire commissioner Daniel Nigro said. Firefighters “found victims on every floor and were taking them out in cardiac and respiratory arrest", Mr Nigro said. “That is unprecedented in our city.” He compared the severity of the fire to the Happy Land social club blaze, which killed 87 people in 1990. A man set fire to that building after getting into an argument with his former girlfriend and being thrown out of the club. Mr Nigro said Sunday’s fire began in a duplex apartment spanning the second and third floors. Firefighters found the door to the apartment open, which apparently allowed the fire to accelerate and spread smoke upwards quickly, he said. The building is owned by Bronx Park Phase III Preservation LLC, a consortium of investing groups in the city. “We are devastated by the unimaginable loss of life caused by this profound tragedy,” the group said in a statement. “We are co-operating fully with the fire department and other city agencies as they investigate its cause, and we are doing all we can to assist our residents.” Sunday’s fire comes days after <a href="https://www.thenationalnews.com/world/us-news/2022/01/05/philadelphia-apartment-fire-leaves-13-dead-including-7-children/" target="_blank">a house fire in Philadelphia</a> killed 12 people, including eight children. <i>Agencies contributed to this report.</i>