The retailers acted after Hong Kong health authorities said they had detected melamine, which has killed four babies and sickened 53,000 in China, in eggs from the Hanwei group.

"We pulled the eggs from the shelves after we heard tests showed another brand from the same producer had the problem in Hong Kong," said Han Xiuzhi, a manager at BHG supermarket in Shin Kong Place, a department store.

US retail giant Wal-Mart said Tuesday it had pulled Hanwei's eggs from its shelves in China, although emphasised it was a precautionary measure and that those that had been on sale had not been found to be contaminated.

Hong Kong health authorities reported over the weekend that they had found melamine in eggs produced by the Hanwei Group.

The discovery of the tainted eggs has led to mounting fears that melamine may have contaminated a larger share of China's food supply than previously thought.

Until the recent development, melamine had been discovered only in dairy products or products containing dairy ingredients.

A staff member at the Parkson Shopping Centre's supermarket, also in Beijing, confirmed Hanwei eggs were no longer on sale.

Also on Wednesday, officials in northeast China said they were looking into reports that eggs from a local company were tainted with the toxic chemical melamine, vowing "severe punishment", state media said.

The government of Dalian, a major port city, said contaminated eggs discovered in Hong Kong were produced by a local company on September 6, the official Xinhua news agency reported.

Xinhua did not name the company, but earlier reports identified it as the Hanwei Group.

The melamine scandal has presented China with one of its worst public relations headaches ever, sending leaders scrambling to patch up China's image as a maker of cheap and relatively reliable goods.

Premier Wen Jiabao pledged over the weekend that China's food exports would meet international norms and win the trust of people globally, promising lessons would be learnt from the nation's milk scandal.

Wen pledged Chinese food exports would "comply with the standards of importing countries," adding China would "seriously draw lessons" from the milk contamination scandal.

"We will use our actions and high quality of our food products to win the trust and confidence of Chinese people and people around the world," he told reporters.

Nevertheless, tainted dairy products continued to flow from China to the outside world.

Thailand's Food and Drug Administration said Wednesday it had found high levels of melamine in chocolate bars smuggled in from China.

In an official statement, the agency said tests showed the Orphic brand of chocolate, discovered in a border town market, contained 34.37 milligrams of melamine per kilogram -- nearly 14 times the permitted level.