BEIJING - Worried shoppers stripped stores of salt in Beijing, Shanghai and other parts of China on Thursday in the false belief it can guard against radiation exposure, even though any fallout from a crippled Japanese nuclear power plant is unlikely to reach the country.

The panic shopping was triggered by rumours that iodized salt can help ward off radiation poisoning -- part of the swirl of misinformation crisscrossing the region in the wake of Japan's nuclear emergency.

The rumours have flown widely. Text messages on mobile phones have circulated about nuclear plumes spreading from Japan throughout Asia. Rumours also spread that salt was adequate protection for radiation sickness.

Supermarkets in the capital of Beijing and many cities across the country have run out of salt in the last several days as a wave of panic buying spread across provinces from eastern Zhejiang to southern Guangdong to western Sichuan.

Prices of salt jumped five or 10-fold in southern Guangdong, the Internet portal sina.com reported.

In Shanghai, Dong Linhua, a 57-year-old factory worker, said he wanted to buy just 2.2 pounds (1 kilogram) of salt but could not even find that.

"Salt is not available in any of the shops," he said. Though Dong said he didn't believe the rumours, he wanted to have the salt for his family.

On Thursday, the country's largest salt maker, China National Salt Industry Corp., issued a statement saying ample reserves were in place and that "panic-buying and hoarding is unnecessary," according to the official Xinhua News Agency.

The Ministry of Health posted information on its websitects of radiation poisoning, but regular table salt doesn't contain enough iodine to block the poisoning, according to health experts.

The Chinese government also weighed in Thursday, with Foreign Ministry spokeswoman Jiang Yu saying, "I do not see any necessity to panic."

The National Development and Reform Commission issued an urgent notice ordering local authorities to take "immediate action to monitor the market prices and resolutely crack down on illegal acts including spreading rumours to deceive the public."

Michael O'Leary, head of the World Health Organization in China, called on governments and individuals to "take steps to halt these rumours, which are harmful to public morale."

O'Leary said the WHO "would like to assure governments and members of the public that there is no evidence at this time of any significant international spread from the nuclear site."