Photographs and video of the building seemed to show that the fire, which was reported just before 7 p.m., appeared to be under control.
Authorities said firefighters rescued 12 people from the building and four people were in hospital in a critical condition.
"We may lose others as well", he said.
Activity from police and fire department officers cut through what otherwise was a generally quiet residential neighborhood that sits a short distance from the Bronx Zoo, St. Barnabas Hospital and Fordham University.
Excluding the September 11 attacks, it was the worst fire in the city since 87 people were killed at a social club fire in the Bronx in 1990.
The fire commissioner said he's unsure whether all the smoke detectors were working in the building.
The fire spread up the stairs and cut off exit points for people on the upper floors. At least 160 firefighters converged on the scene to help battle the flames.
Mr De Blasio later tweeted his thanks to the New York Fire Department "for their bravery and quick action".
The fire started Thursday night around the time that many residents of the 25-unit, five-story building would have been eating dinner. "We won't tell you anything more about it other than they range in ages from 1 to over 50".
Among the victims are a family of four - 2-year-old Kylie Francis, 7-year-old Charmela Francis, 19-year-old Shantay Young and 37-year-old Karen Francis.
"I got scared and freaked out because I thought I was going to fall off the fire escape, but I tried my best", Martinez said.
Still, Nigro said there was nothing structural about the building that contributed to the fire. "I couldn't carry the rest of them", Reyes told the Times.
"I've been calling his phone, it's ringing, but nobody picks up", Bredu said.
Diallo said the apartment building has tenants who hail from all over the world. Red Cross representatives stationed on the block offered blankets and smoke alarm installations to residents.
And in 2007, a fire in the Bronx killed nine children and an adult.
Friday morning Mayor de Blasio said the search for answers in Thursday night's fire is ongoing.
Mensah lived with friends of his father - a married couple and their four children.
Tiger Zinda Hai (Rs 114.93 crore ) beat Raees (Rs 93.24 crore ) to become the highest Bollywood opening weekend grosser of 2017. Five of his films have crosses the Rs 200 crore mark while two have touched the Rs 300 crore milestone.
A supermoon is the term given to full moons which occur at the same time as the moon reaches its closest point to Earth in orbit. A supermoon is a new or full moon that appears bigger to the human eye because it is the closest to the Earth during its orbit.
He made a deal with prosecutors and was imprisoned in late 1999, after pleading guilty to manslaughter and other crimes. Dalton Sr. and Jean Dalton were Dalton Jr.'s parents and Leonna was Dalton Jr.'s niece, according to Omaha police.
Elizabeth also had kind words for her husband, who this year stepped down from most public duties because of his advancing years. Harry said the engaged couple are busy making plans for 2018, adding "we're really looking forward to new year".
Rava also claimed that having a "No Boys Allowed" night was as "repugnant" as a " Caucasian Night " or " Heterosexual Night ". The state's supreme court has previously ruled that "ladies" night'-style promotions in nightclubs break civil rights laws.
Jackson, who finished second place in Heisman voting this year, now has 130 total yards and two touchdowns to his credit. The Bulldogs (8-4), led by interim coach Greg Knox, takes on Louisville (8-4) and stud quarterback Lamar Jackson.
On the National Stock Exchange (NSE), the wider Nifty50 fell by 40.75 points or 0.39 per cent to close at 10,490.75 points. Metal stocks moved up, tracking a rally in copper prices, and pushed the BSE Metal index up by over 2 percent.
The firing of the remaining board members provides further evidence that the Trump administration isn't interested in the issue. A call for new council member nominations went out via a December 1 notice posted on the federal register.
He will succeed Ellen Johnson Sirleaf, Africa's first elected female president, in Liberia's first democratic handover in decades. Weah who was the senator of Montserrado County was once named FIFA World Player and victor of the much-coveted Ballon d'Or.
The actress, 36, caught the eye of 007 producers in her role as Rachel Zane in United States legal drama Suits previous year . George's Chapel at Windsor Castle and marry Prince Harry , 33, in what's sure to be the most talked about wedding of 2018.
Money raised for the event would go toward The Hue Jackson Foundation , which was created to fight human trafficking in Cleveland. I can pick a day and get everyone out there, we'll all be in swimsuits and trunks and snorkels and all that".
Authorities: Florida man tried to electrocute pregnant wife
Upon further search of the residence, deputies found the pair of smart cameras, set up by Wilson's wife, thrown in a toilet. Wilson's wife says he "seemed to be a normal person" until falling a few months ago and refusing to get medical treatment.
United States civil rights activist Erica Garner dies at 27
May you discover the peace in the following life that you merited while you were here. "Her heart was bigger than the world". In a series of tweets after the meeting, Erica Garner again stressed that she wanted to see progress on the investigation.