Iran's Veterinary Organization on Tuesday called on chicken farmers and related officials not to import any birds, poultry and related products from the countries hit by the bird flu, IRNA reported from Tehran.

The Veterinary Organization in a statement also banned import of any domestic or birds of paradise by incoming Iranians and passengers, given the spread of the deadly H5N1 strain of bird flu and the H7 disease in Pakistan.

It also called on all those travelling to the countries hit by the bird flu virus not to visit the sites where any sort of birds are kept.

United Nations agencies Tuesday called for an all-out global effort to combat bird flu and warned the virus could kill millions if it mutates, as China became the 10th Asian country to be hit.

The World Health Organization (WHO) warned millions of people could die if the deadly H5N1 strain of bird flu racing through Asia combined with another human influenza virus that is moving towards the region.

"In my judgment it is possible and so that's why we have to work very hard today, not tomorrow, to contain this, to prevent that mutation," said Shigeru Omi, director of the UN health agency's Western Pacific office.

The WHO has said that while humans have so far only caught bird flu from infected poultry -- usually through contact with animal faeces -- the virus could mutate into a form that can be transmitted between humans.

As the crisis deepened, Thailand prepared to hold international talks aimed at establishing a united front against the disease, the same approach used to fight last year's SARS epidemic which claimed nearly 800 lives.

A six-year-old boy on Tuesday became Thailand's second confirmed victim of the disease which has killed six people in Vietnam and led to the slaughter or death of up to 20 million chickens across the region.

Outbreaks of H5N1 have also been confirmed in Cambodia, Indonesia, Japan and South Korea, with weaker strains detected in Pakistan, Taiwan and Laos.

The United Nations' WHO and Food and Agriculture Organization (FAO), and the Paris-based World Organization for Animal Health, said the spread of the highly pathogenic virus was a 'significant control challenge'.

"We have a brief window of opportunity before us to eliminate that threat," FAO chief Jacques Diouf said in a joint statement, adding that poor nations would need help to carry out culls of infected animals.

Thai Foreign Minister Surakiart Sathirathai said he was confident that the half-day talks, to be held here Wednesday, would help restore confidence.

"The meeting reflects the region's seriousness about tackling the problems," he said. "I think that we can regain confidence."

As well as ministers and officials from crisis-hit countries and other regional nations that have so far escaped the disease, the United States, European Union, WHO and FAO have been invited to attend.

In the latest confirmed outbreak, China on Tuesday said the H5N1 strain had been found among ducks in the southwestern Chinese province of Guangxi.

Some 14,000 birds had been culled at the affected farm and all poultry within a five mile (eight kilometer) radius was quarantined, the Xinhua news agency reported.

Officials from the Ministry of Agriculture and the Ministry of Health have informed the FAO and WHO of the cases, and said exchange and cooperation in bird flu prevention and control was welcome, the Xinhua news agency reported.

The Lao government also said Tuesday that bird flu had erupted in the country, killing hundreds of chickens, but denied it was the deadly H5N1 strain.

Indonesia said it had no plans to fight its outbreak with a mass cull, triggering a call for action from the WHO which urged it to dispose of infected flocks and said vaccination and other measures would not work.

So far only Thailand and Vietnam have reported human deaths from bird flu but Cambodia has two suspected cases and a three year-old boy in Indonesia's resort island of Bali was identified Tuesday as a suspected sufferer.

Vietnam reported that 28 of the country's 64 provinces and cities were tackling bird flu outbreaks but warned that the virus could spread even further.

"We are afraid that we will have a new figure every day," said agriculture ministry official Dau Ngoc Hao.

Malaysia and Singapore said they were both so far free from the disease, but have stepped up measures to prevent infection. Thai Prime Minister Thaksin conceded that the outbreak which has now extended to 13 of Thailand's 76 provinces, from the capital Bangkok up north to the Laos border, could harm the kingdom's economy.

The government approved a 3.0 billion baht (76 million dollar, 61 million euro) relief package to help its laborers and farmers whose chicken stocks have been devastated by the epidemic.

Cabinet ministers also endorsed a plan for a six-month debt moratorium for affected farmers.

The economic threat was underlined by the Asian Development Bank which said Tuesday that the outbreak could cause 'tens of billions of dollars' of damage if it leads to a major travel scare like one caused by the SARS virus.