UPDATED, 4:25 PM: NBCUniversal just issued this one-sentence statement about Dish Network’s lawsuit seeking arbitration in their carriage dispute: “Should Dish proceed with arbitration we will of course participate in the process, and look forward to receiving the fair market value for our portfolio of networks.”

PREVIOUSLY, 12:22 PM: A day after NBCUniversal warned Dish Network subscribers that its cable and broadcast channels might go dark on the service this weekend, the satcaster has hit back. Dish today filed a breach-of-contract lawsuit against NBCUni, claiming the company violated the terms of their 2013 retrans deal. It seeks arbitration to halt the potential blackout.

“Under the conditions imposed by the FCC and Department of Justice in approving the Comcast-NBCUniversal merger, NBC is forbidden from blacking out its networks if a pay-TV provider chooses, in its sole discretion, to exercise its right for binding arbitration,” the satcaster said in a statement announcing today’s legal action. “Regulators implemented these conditions to prevent Comcast and NBC from harming consumers and competition.”

NBC Dish Bravo adFiled in Illinois federal court, the 11-page complaint (read it here) alleges that “NBCU is bombarding Dish’s subscribers with hostile messages and calls to action” in violation of their pact, including running a text crawl of several of its channels, running ads warning of a blackout on Dish starting Sunday, creating a website “specifically to inform Dish customers that Dish may “drop” NBC Programming” and tweeting about the potential blackout.

“Dish has successfully negotiated agreements representing numerous networks in recent months that benefit all parties, including our viewers,” Dish’s statement added. “Dish’s goal is to reach a mutually beneficial deal with NBC. However, based on NBCU’s actions to date, Dish currently expects to file for arbitration, which would prevent NBC from blacking out Dish customers.In the event of arbitration, affected programming would remain available during that process, and for the foreseeable future.”

Attorneys Richard Patch and Katharine Van Dusen of Coblentz Patch Duffy & Bass LLP of San Francisco are representing Dish in the action.