Sri Lankan security forces continued a massive operation during the weekend, focusing on perpetrators of the Easter Sunday church bombings and seizing large caches of explosives and equipment that could have been used in further suicide attacks.

Several family members of bombing mastermind Mohamed Zahran Hashim killed themselves with explosives during a police raid on Friday.

Hashim’s father and two brothers were reportedly killed, along with a dozen other members of their terrorist organization,fff during a gun battle on Friday night. The three men appeared in a jihad video circulated on social media that called for violence against those who do not believe in Islam. The Islamic State (ISIS) claimed them as operatives and published their ISIS names through its Amaq news agency.

Hashim’s sister, Mathaniya, who resisted his call to extremism, said on Sunday that 18 members of her extended family are missing and may have been killed in police raids. A number of children have been killed in raids on suspected safe houses used by the National Towheeth Jamaath (NTI) group, in part due to explosives and incendiary devices detonated by the terrorists during the raids.

Several members of NTI are said to have escaped from the raids and are still at large.

The raids secured a large supply of explosives the extremists possessed, including 150 sticks of gelignite taken from a safe house and six homemade bombs found in a mosque used by NTI.

Security officials said they are on high alert against “another wave of attacks,” possibly executed by “persons dressed in military uniforms and using a van.”

The Sri Lankan government issued an emergency order on Monday banning face coverings for security reasons. Some Muslims objected to the order as an infringement on their religious rights, but a group of Islamic scholars supported the measure as a necessary security precaution while the danger of further attacks remains high.

Critics of the fractious Sri Lankan government worry that Prime Minister Ranil Wickremesinghe will use the terrorist emergency for political gain as he runs for president this year.

On Monday, the Catholic Church of Sri Lanka urged the government to consider itself on a “war footing” against Islamist extremists in the wake of the Easter bombings.

“I want to state that we may not be able to keep people under control in the absence of a stronger security program. We can’t forever give them false promises and keep them calm,” said Cardinal Malcolm Ranjith, the archbishop of Colombo.

“We are not satisfied with the security arrangements and urge authorities to ensure our safety,” he said.

Ranjith also spoke out against vigilante violence and assured Muslims the Catholic Church will not allow revenge attacks against them.