United States reporter Ksenija Pavlovic, who reports from the White House, went against the set rules live-streamed the sound recording of the briefing being held there on July 20.
She used the Periscope app to stream the briefing and later uploaded it on her Twitter account.
Pavlovic streamed deputy White House press secretary Sarah Huckabee Sanders introducing Director of Legislative Affairs Marc Short.
Pavlovic's stream was cut off after roughly 17 minutes of recording, but she tweeted a new live stream that broadcast for another 31 minutes.
The White House had previously banned live audio and video coverage of press conferences on June 29.