Chinese Foreign Ministry Spokesman Hong Lei said on Tuesday that China is willing to cooperate with Turkey to fight terrorism, when responding to Turkish media reports that two Islamic State members from China were arrested by the Turkish military on the Turkey-Syria border on April 7.

According to a statement released by the Turkish General Staff, the suspects were caught within Turkey's territorial boundaries during border patrol activities in a village in the south-eastern province of Kilis.

An investigation into the incident has been launched, the statement added.

Hong Lei said the East Turkistan Islamic Movement (ETIM), a UN-listed terror group, is constantly working to carry out terrorist attacks in the country. It has also colluded with foreign extremists and terrorists and sent people to fight in the wars. The terrorist group has become a big and real threat to world’s peace and security.

China is willing to strengthen cooperation with other countries including Turkey to jointly combat terrorist forces like the ETIM, he added.

There are more than 6,000 Islamic extremists inside Syria. Some terrorists of the IS have been trying to cross the border to get into Turkey illegally amid the thousands of Syrian refugees.

"Some Xinjiang residents have crossed the border illegally to join IS. The group currently has a growing international influence, and Xinjiang is affected by it, too," said Zhang Chunxian, the region's top leader, at a news conference on the sidelines of the annual National People's Congress session in March.

This is the first time that a Chinese official confirmed Xinjiang residents have joined the IS. 

China will enhance intelligence information exchanges and case investigations with Turkish authorities to combat terrorist suspects from the Xinjiang Uygur autonomous region entering the Eurasian country illegally, said an official source who declined to be identified.

The flow of foreign fighters to Middle East, tens of thousands of foreigners from all parts of the world have fled to Iraq and Syria to fight under the banner of terrorist groups such as IS and the al-Nusra Front.

Some of them are returning to their home countries and plan to carry out attacks. The threat from foreign fighters is becoming more and more serious, said Yan Shuai, assistant professor at the Institute of Security and Arms Control Studies at the China Institutes of Contemporary International Relations.