Video report by ITV News Asia Correspondent Debi Edward
Huge amounts of bomb-making material, including thousands of ball bearings, plastic explosives, chemicals and trigger devices which could be made into suicide vests have been discovered in a house in Sri Lanka, sparking fears the Easter Sunday bombings could have been just the start of a massive terror campaign.
The stockpile, discovered in a home in the town of Sammanthurai, 200 miles (325km) from Colombo appears to confirm more horrific attacks were being planned.
The discovery of a so-called Islamic State flag also gives the strongest indication yet that the group responsible for the nine bombings on Sunday is linked to the international terror organisation.
The discoveries came after a shootout at the home between police and suspects.
The grim discoveries come just hours after Sunday Masses were cancelled until further notice.
The Archbishop of Colombo, Cardinal Malcolm Ranjith said church officials had seen a leaked security document describing Catholic churches and other denominations as major targets for attackers.
He also asked the faithful to stay at home for their own safety.
"We don't want repetitions," said the cardinal in cancelling the services.
Cardinal Ranjith also appealed for financial support to rebuild the lives of affected people and reconstruct the churches targeted in the so-called Islamic State-claimed suicide bombings, which killed over 250 people on Sunday.
Authorities in the island nation downgraded the death toll from the previously stated 359.
The announcement comes one day after the Foreign Office warned people not to travel to Sri Lanka "unless absolutely necessary" and the US Embassy in Sri Lanka warned people to stay away from places of worship this weekend over concerns about possible further attacks.
On Friday, authorities urged Muslims not to hold congregational prayers over fears they might be targeted.
However, several mosques did hold prayers under the protection of security forces.
Police are also providing patrols to protect Muslims who are fearful of reprisal attacks in the wake of the atrocity.
Local militants with ties to the so-called Islamic State group conducted a series of suicide bombings on Easter Sunday at churches and luxury hotels in and around Colombo and in the distant seaside village of Batticaloa, as well as three related bombings.
Sri Lanka has remained on edge since the deadly attacks as authorities have pursued suspects with possible access to explosives.
The Easter Sunday attacks have been blamed on National Thowheed Jamaath (NTJ), a local radical jihadist group whose leader, Mohamed Zahran, killed himself in a suicide bombing at the Shangri-La hotel in Colombo.
Police also said they had arrested the second in command of the group.
NTJ have not claimed responsibility for the attacks.
Australia's Prime Minister said it had been confirmed that the Sri Lanka attackers were supported by the Islamic State group, which has claimed responsibility for the massacre.
The group has distributed a video of Zahran and others pledging allegiance to the withered caliphate.
Sri Lankan President Maithripala Sirisena told reporters that about 140 people had been identified as having links to the Islamic State group, and that the government has the capability "to completely control" IS activities in the country.
"We will completely control this and create a free and peaceful environment for people to live," he said.
Police said investigators had determined that the attackers' military training was provided by someone they called "Army Mohideen," and that weapons training had taken place overseas and at some locations in Sri Lanka's Eastern Province.
Police also said they arrested the operator of a copper factory who had helped Mohideen make improvised explosive devices and purchase empty cartridges sold by the Sri Lankan military as scrap copper.
Mr Sirisena blamed Sri Lanka's defense secretary, who resigned Thursday, and police chief, who he said would soon step down, for failing to share information from international intelligence agencies about the plot.
Almost a week has passed since the Easter Sunday terror bombings and tensions are still running high in Sri Lanka.
Shops that should be open remain with their shutters down and streets that would normally be packed appear deserted.
Security warnings of potentially more attacks have spread fear and road blocks remain in place as police stop and search motorists and motorbike riders around the capital Colombo.
Security officials are still hunting for suspects and explosives that are unaccounted for.