KUALA LUMPUR : Malaysian police said on Sunday they had arrested seven alleged Islamic State (IS) militants plotting violence, one of whom was in contact with an extremist blamed for the deadly Jakarta attack.

Thirty rounds of ammunition was also seized along with books and videos about jihad and an IS flag during a series of raids around the country since Friday, national police chief Khalid Abu Bakar said in a statement. The statement did not mention the confiscation of any weapons or explosives but said the group was planning attacks around Malaysia.

One of those arrested had been in communication with Indonesian extremist Bahrun Naim, the statement said. Naim is believed to be the founding member of a Southeast Asian offshoot of the Islamic State group.

Indonesian police say Naim orchestrated - from IS-held territory in Syria - the gun and bomb assault in Jakarta on January 14 that killed eight people including the four attackers.

Two days after the Jakarta attack, Malaysian police said they arrested a man who was planning a suicide bombing in Malaysia in the Islamic State's name. Security forces have been put on high alert in mainly Muslim Malaysia in the wake of the Jakarta attack, which has been claimed by the IS group.

Malaysia has not seen any notable terror attacks in recent years. But concern has risen in the multi-faith nation, with authorities saying scores of Malaysians had gone to join the IS jihad in Syria and Iraq.

Malaysian police regularly announce IS-related arrests but typically offer few details.

The country's political opposition says the government shrouds its anti-terror fight in secrecy, making it difficult to gauge the actual threat level.