Chinese citizens have joined Islamic State, the country's state media said, as China sought to offer further evidence that its domestic security problems are a global concern.

Radicals from Xinjiang have joined the terror group to receive training in Iraq, Syria and elsewhere in Asia, China's Communist-run Global Times newspaper said in a report Monday. Xinjiang is the sprawling region in China's northwest that is home to the restive Uyghurs, a largely Muslim population whose freedoms China has heavily restricted in response to a string of deadly attacks it blames on Uyghur terrorists.

By announcing that its citizens have joined Islamic State, China echoed fears expressed by Western countries – that the violence in the Middle East poses a domestic threat because foreign-trained fighters could return to mount attacks in their home countries.

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Until now, China has not offered any assistance to the U.S.-led campaign against IS and its sole reaction to the chaos in Syria and Iraq has been to withdraw its citizens. Chinese officials routinely say they do not interfere with the affairs of other nations. But China, as one of the five permanent members of the UN Security Council, may now face pressure to get more involved in global counterterrorism efforts.

This week, Chinese Foreign Minister Wang Yi will attend a summit on global terrorism hosted by Mr. Obama at the United Nations General Assembly. "We believe the world should make concerted efforts to combat terrorism and safeguard international peace and stability," China's Foreign Ministry spokeswoman Hua Chunying said Monday.

The existence of ties between Chinese militants and the Sunni extremists who have taken control of parts of Syria and Iraq also adds a new complexity to how Western nations must respond to China's heavy-handed domestic anti-terrorism policies.

The Global Times quoted an unnamed "anti-terrorism worker" who said the Xinjiang militants joining Islamic State "not only want to get training in terrorist techniques, but also to expand their connections in international terrorist organizations through actual combat to gain support for escalation of terrorist activities in China."

The official acknowledgment legitimizes reports from recent months that suggested Chinese citizens had joined efforts to join the cause. The paper said four suspected militants from Xinjiang were arrested in Indonesia this month.

In September, pictures posted to Facebook by the Iraqi Ministry of Defense showed a captured man identified as Chinese, but that claim had not until Monday been confirmed. In July, Wu Sike, China's special envoy on Middle East affairs, said 100 Uyghur militants had travelled to the region for training. Islamic State leader Abu Bakr al-Baghdadi in July was quoted as saying China is at the top of a list of countries where he intends to expand operations, specifically calling out Chinese policies in Xinjiang.

China has strictly curbed religious practice, dress and mobility in Xinjiang – a policy Uyghurs there say specifically targets them. China has blamed a string of terror attacks in recent months on Uyghur separatists; some experts say the repression of Uyghur freedoms has contributed to radicalization. Foreign intelligence and terror-monitoring services say some 400 Uyghur people are in the tribal areas of neighbouring Pakistan working with Taliban and other extremist groups there. An online video posted last year to show a group of 13 young purportedly Uyghur boys – some appearing to be barely grade-school age – standing in a line firing AK-47s.

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The presence of Uyghur fighters in a growing number of other nations marks an escalation for China, as it seeks to combat terror activities that have already killed hundreds of its own people and now, through links to sophisticated groups, threaten to kill many more. Though most terror attacks in China have involved knives and vehicles driving over pedestrians, this summer China seized 1.8 tonnes of explosive materials in Xinjiang.

At home, China continues to debate the merits of participating in multilateral counterterror effort. Join the fight, and "we would be more proactive in contributing to such a global cause – . we would no longer be seen as freeloaders," said Shen Dingli, vice-dean of the Institute of International Affairs at Fudan University in Shanghai. But China could then become a target, he said. "Terrorists would attack China and make China more vulnerable."

The presence of Chinese extremists in jihadist groups abroad suggests China has not been "just crying wolf" when it says it is dealing with a terror problem in Xinjiang, said Greg Barton, a professor of Global Terrorism Research Centre at Monash University in Melbourne. Nevertheless, he added, "the anxiety is it will justify Chinese human-rights abuses in Xinjiang."

But there is also suspicion of Western strategy in the Middle East. Li Wei, an anti-terrorism expert with the China Institutes of Contemporary International Relations, said support for Syrian rebels, for instance, is like "feeding tigers, which can create far greater dangers in the future."

Since the Sept. 11, 2001, terror attacks in the United States , he added, U.S. counterterrorism efforts have come with a "huge cost in personnel and material" and "more and more rampant" terrorist activity.

Mr. Li also said the U.S. and Europe are "directly sheltering" members of the World Uyghur Congress. The group, which routinely criticizes Chinese policies in Xinjiang, is largely seen as an advocacy group for greater religious and cultural freedom for Chinese Uyghurs. China sees the Congress as supporting terrorism.