BREAKING: There is a large high-rise fire at the Monteray Apartments located at 5901 Montrose Rod in North Bethesda, Maryland.

I took this video at 12:01 p.m. Thick gray smoke is actively pouring from a utility shaft on the rooftop. More to come...

UPDATE: This is a two-alarm fire. Multiple ladder trucks have their ladders extended, but not all the way to the roof. It appears this building is around 17 stories tall.

The fire alarm system is still sounding. Dozens of people (presumable residents) are standing outside.

Here is a walking video of the large response from Montgomery County Fire Rescue and Police. Around 75 FFs on scene.

The fire appears to be out at this time.

@mcfrsPIO says a crew was working on a rooftop HVAC unit when the fire started around noon.

No word on any injuries.

WATCH: The Monterey Apartments will likely have severe water damage, reportedly caused by a ruptured "standpipe."

In this video you can see the sheer amount of water pouring out of the main lobby entrance.

Standpipes feed water to firefighter hose lines in high-rise buildings.

I've seen at least 100 people standing outside, some with their dogs. Everyone appears to be calm, all things considered.

Again, this fire was on the roof. It's unclear if the fire spread to any residential floors.

As I said in my previous tweet, there is serious water damage.

Here are four still photos I took of today's two-alarm fire at the Monterey Apartments.

And here is a video that a resident took after she evacuated from the building.

The smoke was incredibly thick and black. The fire was thankfully on the roof and not on a residential floor.