BEIJING - The Ministry of Commerce announced Friday that it will start investigating exports of solar-grade polysilicon, a material used in solar equipment manufacturing, from the United States and Republic of Korea (ROK).

An anti-dumping and countervailing investigation on?US exports and an anti-dumping probe on ROK exports have been initiated in response to requests by leading domestic polysilicon manufacturers, including LDK Solar Co, Ltd and China Silicon Corp, the ministry said in a statement on its website.

The ministry said the investigation will be finished before July 20, 2013 but may be extended for another six months under special circumstances.