Nov. 10 (Bloomberg) -- China halted exports of a children's bead toy after the product was recalled in the U.S. because it contained a toxic drug, the official Xinhua News Agency said.

The General Administration of Quality Supervision, Inspection and Quarantine has ordered an investigation and will release the results promptly, Xinhua said late last night. Li Chaowei, deputy director general at the agency, didn't answer telephone calls made today by Bloomberg News.

The U.S. pulled the toys after four children were reported to have fallen ill after swallowing the beads in the U.S. and Australia, Xinhua said. Chinese-made products have been tarnished amid revelations this year of toxic pet food, contaminated vitamins, lead paint on toys and deadly cribs.

``There are always issues of product safety, but this has become political and a source of tension in the trade relationship,'' said David Cohen, an economist at Action Economics in Singapore. ``China is a more important supplier to the U.S. now and Beijing is under pressure to enhance product safety.''

The U.S. bought $170 billion worth of goods from China in the first nine months of 2007, an increase of 15.8 percent from a year earlier. The country is China's biggest export market.

Date-Rape Drug

Aqua Dots, a toy that features small beads that bond with water, contain the chemical 1,4-butanediol, an industrial solvent that the body converts to gamma-hydroxy butyrate, commonly known as the date-rape drug, according to the U.S. Food and Drug Administration's Web site.

Two children in the U.S. who swallowed the beads were hospitalized after they became comatose and later recovered, the U.S. Consumer Product Safety Commission said in a statement. The toys were manufactured in China and distributed by Toronto-based Spin Master Ltd., it said.

Toys on sale in Hong Kong were also found to contain the drug, the city's government said in a statement yesterday. Retailers have taken the products off their shelves, it added.

China, which produces four-fifths of the toys sold in the U.S., has been the focus of several recalls this year, including at least 21 million items recalled by the world's largest toymaker, Mattel Inc.

Overall, 26 million toys and other products made in China have been recalled by companies in the U.S. since August, according to the Consumer Product Safety Commission's Web site.

Safety standards in China are ``a complex issue that cannot be resolved easily,'' given the size of the country's exports, John Wang, a Shanghai-based manager at Intertek Consumer Goods, which supplies testing equipment, said today by phone.

China's products are mostly safe, and the country has particularly stringent controls on food exports, he added.

It is too soon to say how long the current investigation may take because each recall is different, Wang said.

To contact the reporter on this story: William Bi in Beijing at wbi@bloomberg.net ; Nipa Piboontanasawat in Hong Kong at npiboontanas@bloomberg.net