Every now and then, things go wrong during a live broadcast; Remember Janet Jackson and her wardrobe malfunction incident?

Brian Williams, host of NBC's Nightly News, experienced a bit of a malfunction himself Tuesday night, but with a fire alarm instead of a slip.

Moments into the East Coast broadcast about American Airlines' bankruptcy filing, a fire alarm sounded off in the NBC Studios. Williams calmly told the audience and viewers it was just a routine testing and the anchor carried on delivering the broadcast like a pro through the noise.

You'll forgive us, we have a fire alarm announcement going on here, an un-phased Williams said.

Williams, a former volunteer firefighter in New Jersey, also reassured the alarm did not signify any danger for those in 30 Rock, but was merely a drill since Nightly News moved into a new studio last month.

The alarm continued to sound through most of the program, even after commercial breaks until it stopped with just a quarter left for Williams to read without a high-pitched siren in his ear.

With thanks for your co-operation. We hope to get all quiet and see you here tomorrow night, Williams said while signing off the broadcast.

Almost immediately, people flocked to Twitter to question why NBC could not shut off the alarm faster, as it went on through most of the broadcast, and others commended Williams for getting through without battling an eyelash.

This is the first fire alarm in our new NBC Nightly News studio, NBC spokeswoman Erika Marshonall tweeted following the incident. System should have been shut off - but clearly still working out the kinks.

Only East Coast observers saw the fire alarm flub, as NBC re-taped the broadcast with Brian Williams for West Coast viewers of Nightly News.