Two children were among the eight people killed after a New York City apartment building collapsed , officials said Thursday, as rescuers fought the rain in their continued, frantic search for possible survivors.

New York City Fire Department crews were in rescue mode for nearly 24 hours after the horrific collapse at 1321 Flatbush Ave. in Brooklyn, the city’s most populous borough. Eighteen people were injured.

As of Thursday afternoon, just before 3:40p.m., the FDNY announced it had finished it’s rescue operations, saying there were no more victims.

Earlier in the day, FDNY Commissioner Lillian Bonsignore told reporters that “we will be here until we are 100% sure there are no more people trapped.”

Six of the eight people killed were pronounced dead at the scene, Mayor Zohran Mamdani said. Two others died at the hospital.

Before meeting with reporters at the scene, Mamdani said he visited victims recovering at the hospital.

“This has been a very dark evening and morning for our city,” he said. “We are mourning too many people who we loved, and as we grieve and as we rebuild, we will do so together as one city.”

The half-dozen dead adults included a pair of construction workers, according to the mayor.

Of the 18 people injured, four were firefighters and 14 were civilians. One of those injured was listed in critical condition.

“This is a devastating tragedy for New York, and our prayers are with those who are recovering in the hospital and those who have died,” Bonsignore said. “The FDNY mourns with those families, and we promise, with everything we have, we will not stop working until everyone is rescued or recovered.”

The three-story apartment building came down at about 4 p.m. ET Wednesday, triggering a massive response from firefighters and other rescuers.

Rescuers will be using heavier excavation equipment on Thursday that should be able to locate more bodies or survivors, officials said.

“We always assume that there are more people there until we can access the ground,” Bonsignore said. “So until we’ve removed some of the bigger, bigger debris and are able to search beneath them, this will remain a rescue operation.”

The steady rain that pelted New York City on Thursday could slow rescue efforts, but Bonsignore insisted that crews will fight through this challenge.

“We are in the middle of a rainstorm but that will not stop our operations here,” she said. “It will definitely hinder our efforts. But this type of an emergency is something our members train extensively for.”

The collapsed building, with a business on the ground floor and two stories of residential units above, was next to an excavation site where a single-floor building had been cleared.

“We will find out what happened and we will share that information with New Yorkers,” Mamdani said.

There were “five main entities” connected to that excavation project, with crews from those companies working at about 100 construction sites around New York City, Mamdani said.

“Our Department of Buildings is commencing sweeps of those sites today,” Mamdani said.

The ongoing search also impacted neighboring residences, with water mains to 100 nearby buildings shut down “so emergency crews can continue search and rescue operations,” according to a New York City Environment Protection statement on Thursday.

While some Flatbush Avenue residents displaced by Wednesday’s collapse were allowed back into their homes, three buildings were still under vacate orders and much of the neighborhood was still disrupted on Thursday.

Five bus lines have been rerouted as traffic was still closed on Flatbush Avenue between Clarendon Road and Bedford Avenue, Mamdani said.

“I want to take a moment to remember those we have so senselessly lost,” Mamdani said. “These were our friends and our neighbors, parents and children, young families building their lives in our city and immigrants from Mexico, Colombia, Ecuador, Trinidad and beyond. Let us continue to hold close those who have been plunged into unimaginable grief and pray for a full and rapid recovery for every New Yorker injured.”

It wasn’t immediately clear what caused the collapse but Mamdani said the city’s buildings department would conduct a comprehensive investigation of both the construction site and the collapsed building.