BEIJING?- China's commerce ministry called on the United States on Sunday to stop anti-dumping investigations into imports of solar power products from China, expressing "serious concern" and vowing to defend its producers.

US trade officials on Thursday opened investigations into imports of certain solar power products from?China, a move that could have a major impact on the nation's fast-growing solar market.

The US Department of Commerce said it initiated antidumping duty and countervailing duty investigations, which will assess whether the products are being sold in the United States below their fair value, or if their manufacturers receive inappropriate levels of foreign government subsidies.

"The Chinese side expresses serious concern," the commerce ministry said in a statement on its website. "China urges the United States again to carefully handle the current ... investigations, be prudent in taking measures and terminate the investigation proceedings."

China will assess the impact on its solar industry and "resolutely defend" itself through various mechanisms, the ministry said.