IRAQ'S Ministry of Defence has claimed to have captured a Chinese national fighting for the extremist Sunni militant group, Islamic State in Iraq and Syria (ISIS), and posted two photos of an East Asian-looking man with a battered face on its Facebook page.

A short message accompanying the photos that were put up on Monday called the man a "Chinese daash" - daash being an acronym for ISIS.

If the indentity of the man and the authenticity of the images are validated, this could be the first confirmed case of a Chinese ISIS fighter, the South China Morning Post reported.

Mr Wu Sike, China's special envoy to the Middle East, has previously said that an estimated 100 Chinese citizens - mostly Muslim Uighurs from China's remote western region of Xinjiang - may be fighting for ISIS.

The Chinese embassy in Iraq declined to comment on the photos, while the Iraqi government and Chinese foreign ministry have not responded to interview requests from the Post.

Earlier, the US State Department said some 12,000 foreign jihadists from 50 countries have gone to fight in Syria since the conflict began more than three years ago.

In Austria, the authorities said they suspect about 130 residents - most of them foreign nationals - have allied themselves with Islamist militants fighting abroad.

In Asia, Singapore said in July it is aware of two Singaporeans fighting in Syria with their families.

Malaysia has held 19 ISIS-inspired militants who allegedly planned to bomb pubs, discos and a Malaysian brewery of beer producer Carlsberg. They wanted to establish a hardline Islamic caliphate spanning Malaysia, Indonesia, Thailand, the Philippines and Singapore, said police.

Three Malaysian women had also reportedly travelled to the Middle East in a so-called "sexual jihad" to act as "comfort women" for ISIS fighters.

Indonesia, the world's biggest Muslim-majority nation, estimates that 60 of its citizens have joined the fighting.

As many as 150 Australians are also said to be fighting alongside ISIS overseas, including at least one Sydney man and his young son who have posed for photos with a severed head.

ISIS has carried out beheadings, crucifixions and public stonings in areas under its control in Iraq and neighbouring north-eastern Syria, where it has declared an Islamic "caliphate".

Videos that have emerged since August 19 showing the militants beheading American journalists James Foley and Steven Sotloff have enraged world leaders, with US President Barack Obama vowing to "degrade and destroy" the group.