China has intensified inspections and patrols in border regions to stop terrorism suspects who plan to join extreme Islamic forces, government sources said.

"Border police have stepped up efforts to prevent and combat such cases," said one government official who declined to reveal his name because of the sensitivity of the issue.

In recent years, due to the spread of religious extremism through audio and video materials, a number of young Xinjiang extremists have illegally entered Southeast Asian countries.

From there, they usually purchase fake passports and transfer to Turkey or Syria to receive military training with local extremist organizations, then launch attacks in Syria and Iraq, according to the official.

In March, eight Xinjiang terrorists who planned to illegally cross the Chinese border for jihad were stopped by Yunnan border police. They then returned to the provincial capital Kunming and launched an attack at the railway station that caused 31 deaths and more than 140 injuries.

In September, four Xinjiang terrorist suspects were captured by Indonesian police for violating local immigration and counter-terror laws. They will face charges by the local prosecuting department, according to Singapore's Straits Times.

It reported that the four Xinjiang terrorists crossed the Yunnan border and entered Cambodia and Thailand, where they purchased fake Turkish passports and flew to Kuala Lumpur, capital of Malaysia. Then they transferred to the Java islands in Indonesia and participated in a local ISIS branch.

"Through participating in terrorist training, they could accumulate practical experience in launching terrorist attacks, expand their influence and raise lots of funds," the anonymous Chinese official said. "Their final intention is to return to China to plot and conduct more terrorist attacks."

He said that in order to tackle the issue, border police will pay attention to collecting intelligence, especially enhancing judicial cooperation with neighboring countries to share intelligence.

In addition, police will strengthen management and patrols on the border while intensifying pressure on organizers who help them to get across the border, he said.

To eliminate terror acts, the key is to "strengthen law enforcement cooperation with other countries, such as the US, and some Southeast Asian and Middle Eastern countries, to collect and share intelligence and conduct joint operations," said Mei Jianming, director of the Counterterrorism Center at People's Public Security University of China.

"In addition, relevant countries will take effective measures to cut the channel for recruiting Islamic State members and financial support," he said.