Border police seize a "suspect" during an anti-terror drill at the Gobi Desert in Kashgar, the Xinjiang Uygur autonomous region, in May. China is facing a growing threat from extremists who have participated in the Syrian conflict and are planning domestic attacks, an official the Public Security Ministry said. Ke Dawei / Xinhua

Global challenge

China isn't the only country facing this problem.

"These well-trained terrorists, supported by a network of extremist organizations, are a real threat to safety when they return to their home countries. If they initiate attacks, the consequences could be disastrous," said Herry Sudradjat, director of the Regional and Multilateral Cooperation Bureau at Indonesia's National Counterterrorism Agency.

According to Sudradjat, Indonesia has apprehended a number of suspects who are linked with foreign extremist organizations and have received training via the Internet.

"It's not just an issue for one country, but for all of us. Indonesia is an Islamic country, and we want to take more responsibility for coping with new crimes. We are very willing to cooperate more closely with other countries," he said.

Cherdkiat Atthakor, deputy director of the Department of ASEAN Affairs at the Ministry of Foreign Affairs in Thailand, said counterterrorism is a problem that all countries face, and combating it will require international cooperation.

"In addition to strengthening border controls, we also suggest linking data compiled by the relevant authorities about temporary border passes and vehicles crossing the border to control and prevent illegal immigration," he said.

According to the official from the Chinese Counterterrorism Department, the porous border between Turkey and Syria is facilitating terrorist activity. "Foreign terrorists usually first work out a way to arrive in Turkey and then travel to Syria. The long border between Turkey and Syria has become a major route and provides comparatively easy access for extremists," he said.

"Terrorist and extremist organizations are recruiting members via the Internet, which is difficult to detect and counteract."

According to the official from the Chinese counterterrorism authorities, the terrorists suspected of carrying out an attack at the Jewish Museum in Brussels on May 24, 2014, had fought in the Syrian civil war in 2013.

"It was the first terrorist attack in Europe committed by returnees who had participated in the Syrian conflict," he said.

European countries including Germany, France and Belgium, plus a number of Southeast Asian nations, such as Malaysia and Indonesia, have all discovered so-called returnee extremists.

"These returnees have the skills and ability to perpetrate terrorist attacks in their home countries at any time," the official said.