"We are required by statute to follow a process and do a fulsome investigation as per the statute, so that's what we're going to do," Ms Raimondo told Bloomberg News on Thursday on the sidelines of a unrelated news conference in Washington.
The inquiry is governed by a 92-year-old US trade law, and Biden administration officials have stressed it is a"quasi-judicial" process, meant to be free from political interference. The Commerce Department has until Aug 30 to issue preliminary findings in the case. But US solar power advocates have implored the agency to move faster, as the mere existence of the inquiry - and the threat of retroactive duties - has already delayed renewable projects and prompted an Indiana utility to plan to keep two coal plants running longer.