They’re the Big Apple’s latest weapon in its war against terror — Labrador retrievers that can sniff out molecules from bomb-making materials on people walking in crowds, rather than detecting the substances just in luggage or cars.

Most bomb-sniffing dogs zero in on the scent of explosives on objects that are stationary. But there are now about 100 dogs in the US — including several in the city — that have undergone what experts call revolutionary “vapor wake” training, which enables them to pick up explosives’ scents even on someone walking in a crowd of hundreds.

Most of the dogs are in the hands of government agencies such as Amtrak but NYPD officials have expressed interest in the dogs, also, sources said.