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.

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.