One of Twitter's newest functions got a chance to prove its worth just a week after its launch.

During the brief time that the U.S. Capitol was under lockdown on Thursday after gunshots were fired near the building, the Senate Sergeant at Arms pushed out a notification using Twitter's emergency alert system. The company introduced this feature last week.

Twitter offered the following description of the new function:

Twitter Alerts are tweets published by select public agencies and emergency organizations during a crisis or emergency that contain up-to-date information relevant to an unfolding event, such as public safety warnings and evacuation instructions. Alerts will appear highlighted on your home timeline and are instantly sent to your device as a mobile notification.

Those who signed up to receive alerts from @SenateSAA saw the following series of tweets during the lockdown.

USCP investigating reports of gunshots on Capitol Hill. If in a #Senate office, shelter in place. If not go to nearest office. #alert — SenateSergeantAtArms (@SenateSAA) October 3, 2013

USCP investigating reports of gunshots on Capitol Hill. If in a #Senate office, shelter in place. If not go to nearest office. #alert — SenateSergeantAtArms (@SenateSAA) October 3, 2013

#USCapitol shelter-in-place remains. Close & lock doors. Move to innermost part of office & stay away from external doors, windows. #alert — SenateSergeantAtArms (@SenateSAA) October 3, 2013

#USCapitol Shelter in Place has been lifted. You may exit shelter locations & resume normal activities. Thanks for your cooperation. #alert — SenateSergeantAtArms (@SenateSAA) October 3, 2013

Though it may be the highest profile use of Twitter Alerts to date, this is not the first time a government agency has made use of the function. New York City's emergency notification system, @NotifyNYC, sent an alert about a child abduction last Friday.

The U.S. Department of the Interior used a Twitter Alert to inform people on Wednesday that National Parks, wildlife refuges and other lands it manages will be closed during the government shutdown.

Click here for the full list of Twitter accounts currently eligible to send alerts.

Image: Win McNamee/Getty Images