Apparently one lawsuit against its sworn rival wasn't enough; Jawbone has declared all-out war against Fitbit and is suing the company again — this time for patent infringement, according to The Wall Street Journal. A complaint filed by Jawbone in US District Court in San Francisco seeks a sales injunction against Fitbit's fitness trackers and claims that the company has violated a patent covering "a wellness application using data from a data-capable band." This time, Jawbone says it's also taking its case to the International Trade Commission, a move that could potentially halt Fitbit shipments to the United States and leave them held at the border. We've seen it happen before in the legal skirmish between Apple and Samsung.

Last week, Jawbone launched a major legal offensive against Fitbit and five of its own former employees who jumped ship between the two electronics makers, claiming that they stole confidential trade secrets for Fitbit's benefit. The courtroom challenges come as Fitbit moves toward an IPO on Wall Street, and patent lawsuits aren't entirely uncommon during the pre-IPO quiet period.

But as was the case with the initial complaint, Fitbit is again insisting that there's no substance to Jawbone's accusations. "Fitbit has no need to take information from Jawbone or any other company," the company said in a statement. "We are unaware of any confidential or proprietary information of Jawbone in our possession and we intend to vigorously defend against these allegations." Fitbit most recently released the Charge, Charge HR, and Surge fitness wearables. Jawbone has also rolled out the Up 2 and Up 3 over the last few months.