A window-washing gondola’s cable snapped 20 stories up outside a Lower Manhattan skyscraper Monday — leaving two workers dangling in its bucket before ultimately being rescued by firefighters, officials said.

The harrowing incident unfolded just before 9:10 a.m. Monday at 250 Vesey St., officials said.

Firefighters used a wet saw and angle grinder to cut through the window before safely pulling them inside, according to the FDNY spokesman.

The two window-washers walked away unscathed, officials said.