Thousands of birds were being destroyed today after avian flu resurfaced in Malaysia but the source of the outbreak remained unclear, a health official said.

Authorities had already killed 1,359 birds in and around the affected village since the virus was confirmed late Tuesday, said Kamarudin Mohammed Isa, head of disease control at the Department of Veterinary Services.

The cull began after a villager reported the death of 60 of his birds on the western outskirts of Kuala Lumpur, officials said.

The outbreak is Malaysia's first in more than a year.

Kamarudin said there were "a few more thousand" birds still to be destroyed in the area. "It's chickens and other birds, a few quails," he said.

Officials in white protective suits began the cull last night, collecting birds, including pets and geese, for testing and disposal.

After taking swabs, the birds were placed in sacks to be taken away and killed later.

All birds in a one-kilometre radius of the outbreak would be destroyed, officials said.

Isolated outbreak

Kamarudin said authorities were still trying to track the source of the infection.

"This is the thing that we cannot answer. We can only answer after studying the virus," he told AFP .

Officials have called the outbreak isolated and said no other cases have been detected elsewhere in Malaysia.

Neither has the virus spread to humans, Health Minister Chua Soi Lek said.

Malaysia reported outbreaks of the deadly H5N1 strain of the virus in February last year when it appeared in free-range chickens near Kuala Lumpur, triggering the slaughter of tens of thousands of birds.

There were no human cases.

Five other outbreaks followed elsewhere but the country declared itself free of bird flu in June.

H5N1 has killed 188 people and ravaged poultry flocks worldwide since 2003, according to the World Health Organisation.

Scientists fear the virus could mutate into a form easily spread among humans, leading to a global pandemic with the potential to kill millions.