Islamic State fighters in Syria have revealed their latest weapon - an 80-year-old from China believed to be one of the the terror group's oldest jihadis.

In a propaganda video released by ISIS, Muhammed Amin says he left his home country with his family after seeing a video of his jihadi son being killed in Syria.

Chilling footage was also shot inside a school run by ISIS and features a child singing about 'martyrdom' and another issuing a warning to the Chinese.

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Oldest jihadi? Muhammed Amin, 80, left China with his wife, daughter and grandsons to join the terror group

Despite 'ending training camp very well', Amin was not given permission to fight although posed behind the controls of heavy artillery for the propaganda video

Amin and his family are believed to members of the Muslim Uighur in an autonomous territory in China

It is believed Amin was a member of the minority Muslim Uighur in Xinjiang, an autonomous territory in northwest China once known as Turkestan.

'I was subjected to oppression in Turkestan at the hands of the Chinese... for 60 years,' the grandfather told his interviewer - a fellow ISIS fighter.

'I made hijrah (religious journey) accompanied by my four grandsons, my daughter and my wife.'

Filmed holding an AK-47 in some scenes and at the controls of heavy artillery in others, the elderly jihadi, who is dressed in fatigues, says he trained but is not currently fighting.

'I came to Islamic State and went to training camp despite my old age,' he added. 'I went to training camp and I crawled, I ran and I rolled.

'I did almost everything and ended training camp well. After receiving a weapon I asked permission to participate in battle, but he didn't give me permission so I am presently in ribat (base).'

Elderly: Amin boasts in the video that he can walk for two kilometres by foot and 'did almost everything' at training camp

The elderly jihadi from China, dressed in fatigues, says he went to a training camp but is not currently fighting

The jihadi, who says he was a imam in China, says Muslims face oppression in his home country.

The video, believed to have been filmed in Syria, cuts to scenes inside one of the terror group's schools, where children sit inside a classroom wearing hats bearing the recognisable ISIS logo.

It will certainly unsettle the Chinese security authorities; they have they own very real jihadist threat and anything that inflames the Uighurs will cause the greatest concern

One child, who looks about 10 years old, tells the camera: 'O Chinese kaffar (non-believers), know that we are preparing in the land of the khilafah (caliphate) and we will come to you and raise this flag in Turkestan with the permission of Allah.'

Anthony Glees, the director of the Centre for Security and Intelligence Studies at the University of Buckingham, says the footage seems to be propaganda aimed at Uighurs.

'It's clearly a rallying cry to all Muslims everywhere,' he told MailOnline. 'Yet the images of foot soldiers and this wizened man, looking a bit like a hobbit, trekking his way across vast swathes of wasteland to get to ISIS, is curiously old fashioned. No high-tech warfare here.

'The tenor of the entire video is that ISIS is now fighting a 'crusade' in reverse: Muslims from all over everywhere are flocking to fight for the caliphate.'

ISIS footage: The propaganda video - like many of the terror group's others - has high production values

Classroom: Children wearing hats bearing the ISIS logo are filmed learning in one of the terror group's schools

Earlier this year, Chinese officials claimed Muslims from Xinjiang were travelling to Syria and Iraq to join ISIS - before returning home to take part in plots against the communist rule.

Authorities in the western region said they were planning to strengthen a crackdown on terrorism and extremism in the area, home to the minority Muslim Uighur, some of whom want their own independent state.

China has previously expressed concerns about the rise of ISIS, fearing it will fuel unrest and violence in Xinjiang, where some seek to set up an independent state called East Turkestan.

Xinjiang has seen repeated violence, as members of the Muslim Uighur have bristled under what they say is repressive Chinese government rule.

Beijing has previously blamed the violence on Islamic militants with foreign connections who are seeking an independent state in Xinjiang, but has offered little evidence and ignored calls for independent investigations.

Uighur groups say police have used indiscriminate deadly force against people protesting the government's policies in the region.

One child (right), who looks about 10, issues a chilling warning to Chinese non-believers from the classroom

This child is filmed singing a song about 'martyrdom' in one of the most chilling pieces of footage in the video

Attacks blamed on Uighurs have also occurred in other parts of the country, including a car which plowed into Beijing's Tiananmen Gate in 2013, killing five people.

Many of the group, who have traditionally followed a moderate form of Islam, have also begun adopting practices more commonly seen in Saudi Arabia or Afghanistan, such as full-face veils for women in the face of the crackdown.

Some Xinjiang cities have placed restrictions on Islamic dress, including the capital Urumqi, which banned the wearing of veils in public late last year.

Professor Glees added: 'It (the video) will certainly unsettle the Chinese security authorities; they have their own very real jihadist threat and anything that inflames the Uighurs will cause the greatest concern.

'They will fear further Uighur attacks in China.'