A US trade judge has found that Google infringed on five Sonos patents

On Friday, a US trade judge ruled that Alphabet's Google infringed on five Sonos patents related to smart speakers and related technology, a decision that could result in an import ban.

The brief ruling by Charles Bullock, the US International Trade Commission's chief administrative law judge, did not explain why Google's sale of the products violated a 1930 federal tariff law known as Smoot-Hawley, which was intended to prevent unfair competition.

Sonos has been attempting to prevent Google from importing Chinese-made Home smart speakers, Pixel phones, and other products.

Sonos said the preliminary ruling "confirmed Google's blatant infringement" and bolstered its efforts to defend its technology against alleged misappropriation by larger competitors.

The full ITC is expected to review Friday's decision on December 13, according to the commission's website.

According to regulatory filings, the ITC case is part of a slew of litigation between the two companies, including cases in California, Texas, France, Germany, and the Netherlands.

During their years of collaboration, Google claims that Sonos repeatedly sought assistance, and the company eventually integrated Sonos products into its Play Music service and Google Assistant software.

Google and Amazon.com voice assistance technology has been used in some Sonos speakers. Google Assistant is built into Google's Nest smart speakers.

Sonos is based in Santa Barbara, California, and Alphabet in Mountain View, California. Shares of Sonos were up 11.4 percent in after-hours trading.