China has said it will step up the fight against copyright piracy. The country's top trade official also blamed a growing trade surplus on U.S. restrictions of high-technology exports. President Hu Jintao is preparing to visit the United States, where trade is expected to be high on the agenda.

China vowed to increase efforts to protect intellectual property rights, which are routinely violated in the country. Chinese officials said the government will open enforcement offices in 50 cities to handle piracy complaints and to raise awareness of the need to protect intellectual property.

The announcement comes just ahead of President Hu Jintao's visit to the United States, where analysts expect China's growing trade surplus and piracy to be discussed.

Commerce Minister Bo Xilai says the government is working hard to fight piracy and rejects suggestions that China's copyright infringements were causing a growing trade surplus. Bo says he thinks it is more likely that U.S. restrictions on high-technology exports, rather than intellectual property infringements, influenced the trade surplus.

The U.S. government restricts many high-tech exports to China because of security concerns.

The United States says China last year ran a trade surplus of $202 billion. The Chinese government said its March trade surplus with the world nearly doubled from the year before - to just over $11 billion.

In markets across China it is possible to find shops selling pirated copies of the latest Hollywood movies, as well as fake U.S. goods ranging from cosmetics, to car parts to designer clothes. U.S. companies say they lose tens of billions of dollars a year because of pirating in China.

Bo said protecting intellectual property rights is necessary for China's economic development and not because of foreign pressure.

President Hu Jintao heads to the United States April 18. He will visit the West Coast city of Seattle, give a speech at Yale University on the East Coast and meet with President Bush in Washington.