The Ministry of Commerce said that it would open anti-dumping and anti-subsidy probes on US imported polysilicon, as well as an anti-dumping probe on South Korean imports of the raw materials used to make solar products.

The ministry issued the decisions in two statements on its website, citing preliminary evidence from several companies — GCL Poly-Energy Holdings, LDK Solar, and Daqo New Energy.

Chinese officials have threatened to impose trade duties on US shipments of polysilicon if the US moved to penalise Chinese solar companies.

Early this year, the United States put two new import duties totaling about 35% on solar equipment from China, citing the country’s unfair support of its industry and illegal dumping of inventories in the US market.

China’s solar manufacturers such as Suntech Power Holdings STP.N, Yingli Green Energy YGE.N and Canadian Solar CSIQ.O have criticised the tariffs set this year as a threat to their young industry that will slow its growth by raising costs.

If punitive tariffs are adopted, it would likely impact importers such as US polysilicon maker Hemlock, the world’s largest, and South Korea’s largest producer, OCI Corp.

U.S.-based MEMC Electronic Materials would also be affected.

Though not in a trade war, China and the United States are vocal in their criticisms over the other’s trade policies.

Washington says China’s attacks are largely tit-for-tat retaliations for valid US complaints, while China suggests the White House is simply “China-bashing” in an election year.

Research firm JI Asia analyst Felix Fok said downstream customers, such as WAFER manufacturers, would struggle if China passed on the import tariffs against polysilicon imports.

“China is doing this because some of its companies are basically on their knees,” Fok said, referring to more than a year of losses suffered by the sector.

China’s solar companies hold more than 60% of the global market. The US market alone accounts for about 20% of sales of China’s largest solar panel manufacturers.