The United States investigation into alleged subsidies for Chinese coated paper violates WTO rules, said Chong Quan, spokesman of China's Commerce Ministry, on Tuesday.

Chong said China has provided data and legal evidence proving the investigation was "improper", said Chong.

"The US decision does not abide by WTO rules and breaks its own laws and regulations," said Chong.

"The United States ignore China's great achievement in the market reform over the past twenty years and insisted to treat China as a non-market economic country," he said.

"The US decision did not comply with consensus the two countries have reached that resolving dispute through negotiation, " he said.

The Chinese government would closely monitor developments and reserve the right to safeguard the legitimate rights and interests of the Chinese side, he said.

Each year China exports 300,000 to 500,000 tons of coated paper, which includes the high quality glossy paper used for magazines or wrapping paper, according to Chinapaper.net.