The BBC has complained to the Conservatives about a Facebook advert that uses edited footage of its news reporters and presenters.
The BBC says the material has been taken out of context and its lawyers have asked the party to remove the ad.
The 15-second video was first shown on Thursday afternoon and has so far been seen by more than 100,000 users.
The Conservatives said the footage had "not been edited in a manner that misleads or changes the reporting".
Three clips of BBC reporters or presenters - political editor Laura Kuenssberg, News at Ten presenter Huw Edwards and political correspondent Jonathan Blake - speaking in recent broadcasts are used to describe the situation in Parliament.
"Pointless delay to Brexit" and "another Brexit delay" are among the lines of BBC News commentary used.