Hollywood’s streaming wars are growing more intense.

Months after Walt Disney blocked Netflix from advertising on entertainment-focused outlets like ABC and FX, NBCUniversal said Monday that it would not accept commercials  “at this time” from rival streaming services on Peacock, its own subscription-based streaming-video outlet.

Laura Molen, a president of NBCUniversal’s ad sales and partnerships, indicated the company could be open to taking those commercials in the future. NBCU has launched Peacock slowly, making it available to Comcast subscribers and is getting to launch it more widely in July. As part of that process, NBCU solicited early ad support from a limited number of sponsors, including  Capital One, L’Oreal, Molson Coors, Subaru, Verizon, State Farm, Target, Unilever, and Eli Lilly, and has vowed not to run more than five minutes of advertising per hour on the service.

Even so, ads from streamers and the technology and entertainment giants behind them have become one of TV’s biggest categories in recent months. The Super Bowl, the Emmys and the Oscars have been filled with hard-to-miss ads from Netflix, HBO and Amazon. As AT&T readies the launch of its HBOMax and other services jockey to get consumers to subscribe, that activity is likely to increase.

Molen did not indicate the company won’t run ads from streaming services on NBCUniversal’s TV networks.

In October of last year, Walt Disney stopped accepting commercials from Netflix on its non-ESPN networks, citing a policy that required streaming-video rivals to have a broader relationship that might go beyond advertising in order to gain acceptance.

NBCU’s move further revives a policy from years ago under which TV networks were much more circumspect about taking competitors’ ads. ABC, NBC and CBS used to bar HBO from running many of its commercials on their air, seeing series such as “Rome” or “The Sopranos” as direct competition with their own primetime offerings. Indeed, the big broadcast networks used to bar ads  featuring actors starring in series that ran on competitors. In 1997, for instance, General Motors’ Cadillac ran an ad featuring actor Dennis Franz as a cop handing out a ticket. At the time, he starred as a police detective on ABC’s “NYPD Blue.” CBS and NBC rejected the spot.