Kuala Lumpur - Five suspected ISIS militants from Malaysia have returned to the country, with three of them nabbed by the police and two still at large, the New Straits Times (NST) reported yesterday.

The authorities told the newspaper that the two men are under surveillance, amid concern that they could become recruiters for the extremist Islamic State in Iraq and Syria (ISIS) group, which also calls itself Islamic State.

The three Malaysians claimed during interrogation that they returned as they were unhappy about fighting alongside different militant groups in Syria, with the slightest disagreements at times leading to gunfights.

They also claimed to their investigating officers that they had to come home to take care of family matters.

Their return has raised alarm as authorities have said the fighters from the battlefront might promote their extremist ideology to others or become local militant leaders.

One of the three men who was nabbed was one Mohamad Fauzi, NST said, whom police describe as a "Tier One personality" and who is known among his comrades as Abu Dayyan. Prior to his return on Oct 27, he had been in Syria with another Malaysian, known as Abu Naeem, who was described as a "commander of all operations", in a propaganda video by ISIS.

A worry for the police is that several more battle-hardened Malaysian militants could have returned home, as they could have slipped through the screen of international law enforcement agencies.

"It is hard for police to ascertain how many of them have come back, when their going to Syria was not properly tracked," a police source was quoted as saying by the newspaper.

Officials have said that at least 37 suspects linked to ISIS have been detained since April but more, including key recruiters, remain at large.

The Home Ministry will propose an anti-terrorism law soon to strengthen existing legislation to allow early prevention of recruitment.