The Trump administration said late Monday that it will require drugmakers to reveal the list prices of their medicines in television ads. The move sets the stage for months or possibly years of battle with the powerful industry.

The proposed rule would require pharmaceutical companies to include the price in a TV ad for any drug that costs more than $35 a month. The price should be listed at the end of the advertisement in “a legible manner,” the rule states, and should be presented against a contrasting background in a way that is easy to read.