Kazakhstan has confirmed an outbreak of the highly contagious H5 bird flu virus in wild swans, by the Caspian Sea.

The World Organisation for Animal Health (OIE), citing a report from the Kazakh agriculture ministry, said on Friday that two swans were found dead in the coastal city of Aktau in the west of the country.

Different strains of bird flu have been spreading across Europe and Asia since late last year, leading to large-scale slaughtering of poultry in certain countries and some human deaths in China.

Last month, Slovakia also reported an avian influenza outbreak, and more than 22.5 million were culled in South Korea.

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The strain of flu found in birds sometimes migrates to humans, which could be fatal.

This has worried the public health community. Some predict a worldwide epidemic if human-to-human transition becomes possible, according to a study by Yale University.

Kazakhstan is due to host the Syria peace talks in the capital Astana on January 23.

Delegates from Turkey, Iran, Russia and Syria's opposition groups are descending into the country to discuss a possible solution to the six-year conflict.