BEIJING — Curbs on exports of industrial raw materials were implemented by China after what it called unfair-trade complaints by the U.S. and Europe were lodged. China also has filed its own challenge to a U.S. ban on imports of Chinese poultry, according to The Associated Press.

The curbs comply with Chinese trade commitments and are meant to protect the environment, explained the Chinese Ministry of Commerce.

On June 23, the U.S. and E.U. filed World Trade Organization complaints accusing Beijing of unfairly favoring its domestic steel, chemicals and other industries by restricting foreign rivals' access to key materials. China is a major supplier of several materials.

"The goal of the Chinese side's policy on the relevant exports is to protect the environment and natural resources, and the Chinese side considers the relevant policy to be compliant with W.T.O. regulations," the ministry said in a written statement. It added Beijing hopes to resolve the dispute through dialogue in the Geneva-based W.T.O.

Tensions over Beijing's industrial policies have been aggravated by the plunge in world trade and have been further increased by the addition of these complaints. China said it has raised taxes on exports of coke, steel, fertilizers and other goods to curb the growth of industries deemed "too dirty" or "energy-intensive" and to ensure supplies at reasonable prices for domestic buyers.

The materials cited in the U.S. and European complaints include coke, bauxite, magnesium and silicon metal. The communist government also has rankled some of its trading partners by trying to boost exports through tax breaks and other aid to Chinese producers, which threatens to pump more goods into already glutted global markets.

Analysts expect President Barack Obama's administration to file more trade cases against China following his campaign promises to take a tougher approach with U.S. trading partners. Both Beijing and Washington have imposed measures favoring domestic industries in their economic stimulus packages enacted in response to the global slowdown.

The Ministry of Commerce said June 24 that Beijing has asked the W.T.O. to investigate a U.S. ban on imports of Chinese poultry. The two countries banned imports of each others' poultry in 2004 following an outbreak of bird flu. Beijing lifted its ban after a few months and complains Washington has failed to follow through on a pledge to open its market to Chinese poultry exports.

Beijing has asked the W.T.O. dispute resolution mechanism to create a group to investigate the U.S. ban.