PETALING JAYA (THE STAR/ASIA NEWS NETWORK) - The police crackdown on Islamic State in Iraq and Syria (ISIS) militants here has dealt a blow to the terror group's use of Malaysia as a transit point for recruits headed to Syria to join its ranks.

A recruiter in Syria for the militant group just posted a warning on the ISIS website urging Indonesians not to transit in Malaysia, saying that to do so would be suicidal.

Using the name Abu Hud, he said that many Indonesians who transited in the country in recent months while travelling to Syria to join the ISIS ranks had been arrested before they could reach their destination.

"If Indonesians ask where they have to go through, please do not give advice to pass through Turkey or any place where they have to transit in Malaysia," said the notice posted on the blog.

"It is tantamount to suicide, It is not safe anymore!"

Deputy Inspector-General of Police Commissioner Seri Noor Rashid Ibrahim said that while the counter-terrorism division hunted Malaysians trying to join ISIS, it kept an eye out for ISIS recruits of other nationalities.

"We are glad our efforts are showing results and are preventing militants from joining IS through Malaysia.

"We will continue our vigilance at all exit and entry points to ensure no one slips through our net," he told The Star yesterday.

The ISIS recruiter, Abu Hud, also advised anyone travelling to join ISIS to not keep anything related to the terror group or its activities, be it a video, book or sticker. He said several Malaysians and Indonesians who were on their way to Syria a few weeks ago were found out that way and arrested.

Abu Hud also answered a question from an anonymous person who asked if he should make a detour or go straight to Turkey.

"It depends, but (doing) anything to throw off the kaffir (a term for non-Muslims) is good, he answered.

"I'd advise taking a detour. Like Beijing or Hong Kong if you can afford it."

The police have repeatedly said that they will not allow Malaysia to be a hideout, base or transit point for terrorists and militants.

The diverse international air routes from Kuala Lumpur make it easy for anyone going from this region to reach Syria via Turkey, especially militants trying to avoid detection. Several Indonesian ISIS recruits have pretended to be Malaysians and travelled to Turkey while some Malaysian ISIS recruits have gone to Indonesia and then to Turkey.

With Malaysia no longer a viable option, sources have told The Star that the militants would probably switch to alternate routes such as via Brunei, Hong Kong, China and some European countries to get to Turkey and then Syria.

"The authorities discovered that Brunei was one alternative route used by Malaysian militants following an arrest last month.

"It is possible that Indonesian militants may be using the same route as well," a source said.

Attempts have also been made to fly to Saudi Arabia on the pretext of performing the Umrah and to Jordan before securing passage to ISIS-controlled territories, according to the sources.

However, another source called for caution, saying that the warning on the ISIS website could be a ruse to throw the authorities off guard.

Datuk Noor Rashid said Bukit Aman was working with the intelligence organisations of neighbouring countries to further enhance its security capabilities and effectiveness.

Since February last year, the Bukit Aman Special Branch Counter Terrorism Division has arrested 51 suspected Malaysian militants.

Last month, 12 Indonesians - including five children - were arrested in Selangor during a large-scale operation. They were planning to fly from KL airport to Turkey and then to Syria.

A study by the Institute For Policy Analysis and Conflict (Ipac) said that based on Facebook pages it monitored, it was clear that ISIS supporters in Indonesia and Malaysia were "friending" one another.

"It is also clear that some Indonesians were identifying themselves as Malaysians, perhaps as a security measure, just when Indonesians and Malaysians were going to Afghanistan in the early 1990s and many identified themselves as Filipinos.

"To further throw possible trackers off the scent, Indonesians headed for the Middle East are reportedly leaving from Malaysia while Malaysians are leaving from Indonesia," Ipac added.

"There is so much travel between the two countries that it would not raise any red flags with immigration authorities on either side," according to the study, which was released on Sept 24 last year.

In July last year, Ipac said the Indonesian-Malaysian connection in Syria took on a new facet, with the formation of a katibah nusantara, or special unit for Malay-speaking mujahidin in ISIS.

"Before the declaration of the caliphate, there were relatively few Malaysians with ISIS; more had joined the Ajnad Al-Sham Islamic Union based in and around Damascus.

"One of the few to join ISIS was Ahmad Tarmimi, who became the first Malaysian to die as a suicide bomber in Iraq in late May 2014."

By early August, at least 22 Indonesians and Malaysians had come together under the IS banner in the town of Al-Shadadi, Hasaka province.

Ipac said this group discussed the desirability of forming a katibah, a military unit roughly equivalent to a company, comprising 100 men.

"A Malay-speaking unit made sense militarily because communication was a perennial problem. Most Indonesians were not fluent in either English or Arabic.

"It also made sense given the ISIS agenda to expand the reach of the caliphate to other areas, including South-East Asia," the study said.