Tied to its increased focus on video, Facebook confirmed today that it will begin testing pre-roll ads in spots where users “proactively” seek out content, such as its new Watch offering.

RELATED: Facebook Unveils ‘Watch’ Platform

“While pre-roll ads don’t’ work well in News Feed, we think they will work well in Watch because it’s a place where people visit and come back to with the intention to watch videos.” Maria Angelidou-Smith, product management director, and Abhishek Bapna, product manager, at Facebook explained in this blog post.

They said the effort will start with six-second pre-rolls as Facebook works to understand what “works best for different types of shows across a range of audiences.”

This monetization-focused move comes as video becomes a core focus for Facebook and as mobile continue to be a main ad revenue driver. In Q3, Facebook mobile ad revenues, at $8.9 billion, were 88% of all ad revenue for the period, up from 84% of ad revenue in Q3 2016.

RELATED: Facebook Willing to Experiment with Video

The coming pre-roll ad test was just one of a set of updates from Facebook with respect to video.

It’s also updating the News Feed ranking to improve distribution of videos that users actively want to watch, focusing, for example, on those that have strong repeat viewership.

Facebook is also tweaking its guidelines for ad breaks and providing new metrics for publishers and creators to gauge ad performance.

Starting next month, Facebook will also focus the expansion of ad breaks on shows, with eligibility shifting to videos and episodes that are at least three minutes long. Previously, ad break-eligible videos were a minimum of 90 seconds.

“Our consumer research showed that moving from 90 second to three minute videos with Ad Breaks improved overall satisfaction,” the Facebook execs noted.

YouTubesays more advertisers are using its six-second bumper ads, which were introduced last year.

Robert Kyncl, YouTube's chief business officer, speaking at the Dmexco conference in Germany Thursday, said that one in three of YouTube’s large customers are now using bumpers to get their message across quickly to viewers.

There has been a 70% increase in the number of YouTube customers adopting the shorter ad format from first quarter 2017 to second quarter 2017.

YouTube is also launchinga leaderboardthat ranks the top six-second spots from around the world.

In the television business, Fox Networks Group has beenaggressively pushing six second ads. The shorter commercials ran duringFox’s Teen Choice broadcastand can now been seen in sports programming includingNFLbroadcasts.

Read more at B&C.

Fox said it would be offering advertisers on its sports programming the six-second ad format introduced by YouTube.

Fox joined YouTube in endorsing the shorter commercial unit and first aired a six-second spot during its Teen Choice Award show earlier this month.

RELATED: Fox Joins YouTube in Endorsing Six-Second Ads

The short spots will run on Fox’s America’s Game of the Week NFL games during the first week of the season on Sept. 10.

Read more at B&C.