A U.S. federal court sentenced the son of a Russian lawmaker to 27 years in prison on Friday over a cyberassault on thousands of U.S. businesses. It is the longest hacking-related sentence ever imposed in the United States.

Roman Seleznev, 32, was found guilty last year by a jury in Seattle of perpetrating a scheme that prosecutors said involved hacking into point-of-sale computers to steal credit card numbers and caused $169 million in losses to U.S. firms.

The Russian government has maintained that his arrest in 2014 in the Maldives was illegal. It issued a statement on Friday criticizing the sentence and said it believed Seleznev's lawyer planned to appeal.