NBC News said Thursday it was shutting down its popular Breaking News services for alerts on developing stories at the end of December, citing a lack of revenue.

While Breaking News has a large following in media and government circles and "news junkies" in the US and worldwide and some 9.4 million Twitter followers, the service "has not been able to generate enough revenue to sustain itself," according to a memo to its staff. 

The shutdown underscores the conundrum facing news organizations, seeking to deliver breaking stories quickly to people on all their devices without a strong revenue model.

"We're true believers of news that isn't designed for clicks, but a service that helps people and companies make smarter, safer decisions," co-founder Cory Bergman tweeted.

"As we discovered, such a model doesn't fit with advertising, and despite a surge of interest in our premium data, the money has run out."

Breaking News is a "suite of digital products" that includes a website, mobile app and Twitter feed. It has some 20 journalists as a standalone entity within NBC News Digital, a unit of Comcast's NBCUniversal. 

The initiative was launched by Michael Van Poppel in 2007, and taken over in 2009 by MSNBC Interactive, before moving to NBC News Digital Network in 2012.

"Breaking News will cease operations by the end of this month," the staff memo said.

"Cory Bergman and his incredibly talented team — in Seattle, LA, Chicago, New York and London — will remain with the company until late January, and we will be using the time between now and then to try and find new roles for each of them... We will also be working with Cory and team to incorporate the best of Breaking News’ features into other NBC News products," it added.