Police are on alert and have increased patrols in Jalan Alor and surrounding areas in capital city Kuala Lumpur following credible information on a potential terrorist attack following the arrests of several militants from the Islamic State of Iraq and Syria (Isis) in the past month.

"Yes, we are on alert. More policemen have been sent to the ground," a Kuala Lumpur police source told The Malaysian Insider.

"It is believed to be retaliation for the crackdown against the militants."

The US Embassy in Kuala Lumpur had also advised its citizens to avoid Jalan Alor and surrounding areas today.

Last month, Malaysian police arrested 10 suspected Isis members in multiple raids across the country.

Those arrested included six security forces personnel, a former interior designer and a kindergarten teacher, it was reported.

The suspects – eight men and two women – were detained by the special counter-terrorism division in six separate areas, including Kuala Lumpur.

Inspector-General of Police Tan Sri Khalid Abu Bakar said then that the suspected militants were believed to be plotting an attack on Malaysian soil, and were collecting funds to assist Malaysian Isis members wanting to travel to Syria.

The Diplomat, a current-affairs magazine, reported two days ago that Indonesia’s counter-terrorism chief has warned that the Isis is collaborating with smugglers to bring foreign fighters to Indonesia from Malaysia.

Saud Usman Nasution, head of Indonesia’s counter-terrorism agency, told the Australian Broadcasting Corporation that the Isis fighters arrived from Malaysia in Sumatra, after which they are taken to Poso in central Sulawesi, believed to be a training ground for Isis fighters.

“We see that some foreign terrorist fighters from overseas come to Indonesia. First they leave Malaysia and head for Pekanbaru (Sumatra) to Puncak (west Java) — it’s all facilitated by asylum seeker networks, then from Puncak they would leave to Makassar and Poso, with facilitation from Isis network,” he said.

“So we need to stay vigilant, more so because there is information that in Malaysia, there are thousands, a lot of foreign terrorist fighters there who are about to be deployed – we don’t know where to – under the network,” he added. – September 24, 2015.