Malaysian police said on Friday that they have detained another 15 suspected militants, including several foreigners, for smuggling firearms and plotting attacks on places of worship.

National police chief Mohamad Fuzi Harun said six Malaysians, six Filipinos, a Bangladeshi restaurant owner and a couple from a north African country were detained between March and May.

Among the Malaysians was a 17-year-old student who made six Molotov cocktails he planned to use against entertainment outlets, churches and Hindu temples in Kuala Lumpur, Fuzi said.

The student, a suspected Islamic State member, tested one of his devices in an open area and was detained in April, an hour after he produced a video on social media warning of the attacks, he said.

The police chief said a 51-year-old Malaysian woman was also held on May 9 during general elections for planning to ram a car into non-Muslims at a voting centre. “In addition, the suspect also planned to drive into non-Muslim worship places using a car filled with gas cylinders as explosives,” he said.

Fuzi's statement said a 33-year-old Malaysian was detained after he was deported by Turkey for trying to slip into Syria to join the Islamic State. Two other Malaysians had planned to kidnap and kill police officers and also attack places of worship, it said.

Fuzi said the African couple, both in their early 20s and suspected of having IS ties, were detained in April and since have been deported. Their specific home country wasn't disclosed.

The 41-year-old Bangladeshi was believed to be involved in smuggling weapons for terrorists.

Another Malaysian and six Filipinos, aged between 22 and 49, were held in April in Sabah state on Borneo island for being part of a militant cell collecting firearms to wage “jihad” in Marawi city in the Philippines, he said.

Marawi was the scene of a six-month militant siege last year. Hundreds of people suspected of having ties to the militant Islamic State have been detained in Malaysia in the past few years.