Nielsen has filed a lawsuit in U.S. District Court in New York seeking an injunction against a new measurement service from rival comScore that it says makes use of Nielsen’s Personal People Meter data in violation of previous agreements between the companies.

In the latest legal skirmish between the audience measurement companies, Nielsen claims that comScore is breaching a remedial agreement for using Nielsen’s PPM data “to provide services in the ‘CrossPlatform’ market (at minimum, TV and online audience measurements). But the suit (read it here) says comScore’s new Extended TV offering, which “will provide television audience measurement in the absence of online audience measurement for virtually all programming and the vast majority of networks,” the lawsuit states.

It adds: “Nothing in the Remedial Agreement or any other contract between the parties permits comScore to do that. Indeed, the Agreement explicitly bars comScore from using PPM data for ‘individual, stand-alone services’ like linear television measurement services.

Nielsen says such an offering violates its rights under the agreement and, “if comScore is not enjoined, Nielsen will suffer irreparable harm to its business through loss of important customers and decreased market share.”

ComScore, which became a Nielsen rival after acquiring Rentrak in February 2016, has of late had to pay millions in cash and stock to settle class action suits, and has also been dealing with accounting issues. Most recently, on September 11, its share price took a hit after the company revealed it has a new CFO, lost seven board members, would make a “strategic review,” and — with its financial review “more complex and time-consuming than previously anticipated” — said it won’t file statements for 2015, 2016, and 2017 until at least March 2018.

Nielsen and comScore had settled previous digital measurement patent suits in 2011.

“We​ ​believe​ ​[today’s]​ ​legal​ ​filing​ ​speaks​ ​for​ ​itself,” a Nielsen spokesman told Deadline. “ComScore’s​ ​use​ ​of​ ​Nielsen​ ​PPM​ ​data​ ​in​ ​its planned​ ​Extended​ ​TV​ ​service​ ​violates​ ​the​ ​parties’​ ​agreement​ ​by​ ​offering​ ​linear television​ ​measurement​ ​without​ ​online​ ​viewership​ ​while​ ​claiming​ ​Extended​ ​TV​ ​is​ ​a cross​-platform​ ​service.

“This​ ​requires​ ​Nielsen​ ​to​ ​ask​ ​the​ ​courts​ ​to​ ​stop​ ​the​ ​introduction of​ ​Extended​ ​TV​ ​until​ ​this​ ​matter​ ​can​ ​be​ ​resolved​ ​through​ ​arbitration. We​ ​will​ ​make​ ​no further​ ​comment.”