Investigators have dismantled a major part of the network linked to Sri Lanka's Easter Sunday bombings, Prime Minister Ranil Wickremesinghe said on Tuesday, but warned the chance of further Islamist militant attacks could not be ruled out. All of the members of the Easter Sunday attacks cell that pledged allegiance to ISIS are either dead or arrested, Sri Lankan authorities said. Police have arrested 73 suspected in their ongoing investigation into the suicide bombings at three churches and three luxury hotels that left 257 people dead and hundreds more wounded. Mr Wickremesinghe said the government, which has made major strides in capturing the plotters linked to the April 21 bombings that killed more than 250 people, including 42 foreigners, plans to introduce a new anti-terrorism law. "We have taken measures to normalise the situation," he told parliament. "But we should keep in mind that the threat has not been completely neutralised because it is an issue of global terrorism." They have frozen around $40 million in assets and seized explosive devices, hundreds of swords and $140,000 in cash during the rounding up of the suspects. The latest security assessment suggested that new attacks remained possible and church services were called off for a second week in a row. The faithful celebrated Mass from home watching live on television. But on Tuesday, one of the churches targeted in the attacks, St. Anthony's Shrine in Colombo, opened a section of the church to the public for the first time since the bombing, enabling devotees to pray in the church as was customary every Tuesday. Catholic schools remain closed until further notice after reports said two of their locations were to be attacked last weekend. Government-run schools reopened for students of higher classes Monday but fewer students attended out of fear. Army Commander Mahesh Senanayake on Monday urged the public to resume normal activities trusting in the security forces. "I ask the people not to fear unnecessarily, not to believe rumours...believe in the tri-forces and police that defeated one of deadliest terrorist organisations in the world," he said of the ethnic Tamil separatists who fought a 26-year civil war. The conflict ended 10 years ago.