Facebook has confirmed that it is testing mid-roll video ads inside its Facebook Live video service. The social network confirmed the move in an email to AdAge on Monday.

A source who has discussed the move with Facebook said the ads would appear five minutes into a broadcast and be up to 15 seconds long. This is the first time Facebook has served ads within video content on its network.

The ads will be selected from promoted video campaigns running on Facebook, but brands have the option to opt out if they are concerned that their ad might appear among Facebook Live content relaying bad or tragic news.

Phil Dyte, strategy director at iProspect UK, said the move makes sense for Facebook. He told Mobile Marketing: “Facebook unveiled its 10-year road map in April, confirming video as one of the key products to focus on in the immediate future. In recent months it has become clear that the urgency is real, as Zuckerberg’s company rushes to secure a strong pole position on the emerging live space. In doing so, it skirmishes against the real-time advantages of rival services YouTube, Twitter and Snapchat by leveraging its platform and massive scale – and like these companies, it is searching hard for the commercial model that squares surging demand and smart advertising.

“Nobody truly knows what live video will become, and this latest foray may or may not be the path Facebook eventually go down. But for the time being, it keeps them firmly in contention.”