VIDEO: Firefighters put out a four-alarm fire that tore through an apartment in Upper Manhattan Tuesday night. According to the FDNY, firefighters responded to of a four-alarm apartment fire at Post Avenue in the Inwood section around 7 p.m. Citizen App video shows firefighters battling the fire. They say the fire was located in an apartment on the top floor of the six-story multiple dwelling at the address. It was determined that the fire had extended into the walls which resulted in the fire being upgraded to a second alarm. Conditions then progressed to a point which it was further upgraded to a three-alarm fire, and then a fourth alarm around 8:30 p.m. The fire was placed under control around 10:45 p.m. Two firefighters were taken to North Central Bronx Hospital. There is no word yet on their condition. The cause of the fire has not been determined yet. The investigation is ongoing.