NEW YORK, USA: U.S. companies that import solar panels to the United States are facing up to $70 million in unexpected tariffs, The New York Times reported on Wednesday.

The tariffs could hurt foreign solar panel makers and foreign and American distributors, and strain trade relations between the United States and China, the newspaper reported.

According to the article, U.S. customs decided early this year that because the panels contain a basic electronic device for safety and energy efficiency, they would be treated as electric generators, subject to a duty of 2.5 percent.

The decision is legally binding on most solar panels imported into the United States, the newspaper reported, noting that no one in the industry became aware of it until the last few weeks.

In the meantime, unpaid duties piled up, along with penalties that are likely to double the cost, according to the article.

The Solar Energy Industries Association, a coalition of domestic and foreign companies, argues that American tariffs on solar panels could lead other countries to impose tariffs on American exports, the article said.