KUALA LUMPUR, Malaysia – Malaysian police have arrested an 11th suspect in an operation to break up Islamic terror groups posing as humanitarian organisations, an official said on Saturday.

Police arrested 10 Malaysians earlier in the week during raids in and around the capital Kuala Lumpur and the northern state of Kedah before a man attempting to flee the country was detained on Thursday, said a Home Ministry official.

“Our biggest worry is organizations using humanitarian missions as the basis to train militants,” said Home Minister Zahid Hamidi as cited by Malay-language daily Berita Harian in comments confirmed by the official.

Hamidi said these groups claimed to be on a “jihad (holy war),” according to the newspaper Utusan Malaysia.

The Malay-language publication also reported that police are still tracing a number of other suspects in ongoing investigations.

Malaysia practices moderate Islam and has not seen any notable terror attacks in recent memory, but concern has risen in the multi-faith nation over perceived Islamization.

The Southeast Asian country has been home to several suspected key figures in militant Islamic groups, such as the al-Qaeda-linked Jemaah Islamiyah blamed for the deadly 2002 Bali bombings.

Police have said they are also probing terrorism as one possible reason for the March 8 disappearance of Malaysia Airlines flight MH370.

A source familiar with the arrests told AFP on Monday that those detained were not linked to Jemaah Islamiyah or the disappearance of the jet.

The plane, carrying 239 people, is believed to have crashed into the southern Indian Ocean, but no sign of wreckage has been found despite weeks of search efforts.