Sri Lanka has said it is invoking emergency powers in the aftermath of devastating bomb attacks on hotels and churches, blamed on militants with foreign links, in which 290 people were killed and nearly 500 wounded.
The emergency law, which gives police and the military extensive powers to detain and interrogate suspects without court orders, goes into effect at midnight tonight (7.30pm Irish time).
Police said 87 bomb detonators were found at the main bus station in the capital Colombo, while an explosive went off near a church where scores were killed yesterday when bomb squad officials were trying to defuse it.
A night curfew came into effect at 8pm (3.30pm Irish time), the government announced.
There has been no claim of responsibility for the attack but suspicion was focusing on Islamist militants in the Buddhist-majority country.
Investigators said seven suicide bombers took part in the attacks while a government spokesman said an international network was involved.
Police had received a tip-off of a possible attack on churches by a little-known domestic Islamist group some ten days ago, according to a document seen by Reuters.
The intelligence report, dated 11 April, said a foreign intelligence agency had warned authorities of possible attacks on churches by the leader of the group, the National Thawheed Jama'ut.
It was not immediately clear what action, if any, was taken on the tip-off.
Police said 24 people had been arrested, all of whom were Sri Lankan, but they gave no more details.
International anti-terrorism experts said even if a local group had carried out the attacks, it was likely that al Qaeda or so-called Islamic State were involved, given the level of sophistication.
Two of the suicide bombers blew themselves up at the luxury Shangri-La Hotel on Colombo's seafront. The others targeted three churches and two other hotels.
A fourth hotel and a house in a suburb of the capital were also hit, but it was not immediately clear how those attacks were carried out.
Most of the attacks came during Easter services and when hotel guests were sitting down for breakfast.
"Guests who had come for breakfast were lying on the floor, blood all over," an employee at Kingsbury Hotel told Reuters.
Cabinet spokesman Rajitha Senaratne said an international network was involved, but did not elaborate.
"We do not believe these attacks were carried out by a group of people who were confined to this country," Mr Senaratne said.
"There was an international network without which these attacks could not have succeeded."
The president, Maithripala Sirisena, said in a statement the government would seek foreign assistance to track the overseas links.
Sri Lanka was at war for decades with ethnic minority Tamil separatists, most of them Hindu, but violence had largely ended since the government victory in the civil war, ten years ago.
Sri Lanka's 22 million people include minority Christians, Muslims and Hindus.
Most of the dead and wounded were Sri Lankans although government officials said 32 foreigners were killed, including British, US, Australian, Turkish, Indian, Chinese, Danish, Dutch and Portuguese nationals.
Denmark's richest man Anders Holch Povlsen and his wife lost three of their four children in the attacks, a spokesman for his fashion firm said.
The US State Department said in a travel advisory "terrorist groups" were plotting possible attacks in Sri Lanka and targets could include tourist spots, transport hubs, shopping malls, hotels, places of worship and airports.
There were fears the attacks could spark communal violence, with police reporting late on Sunday there had been a petrol bomb attack on a mosque in the northwest and arson attacks on two shops owned by Muslims in the west.
Traffic was uncharacteristically thin in normally bustling Colombo after an island-wide curfew was lifted earlier today.
Soldiers with automatic weapons stood guard outside major hotels and the World Trade Centre in the business district, a Reuters witness said.
An Australian survivor, identified only as Sam, told Australia's 3AW radio the hotel was a scene of "absolute carnage".
He said he and a travel partner were having breakfast at the Shangri-La when two blasts went off. He said he had seen two men wearing backpacks seconds before the blasts.
"There were people screaming and dead bodies all around," he said. "Kids crying, kids on the ground, I don't know if they were dead or not, just crazy."
There were similar scenes of carnage at two churches in or near Colombo, and a third church in the northeast town of Batticaloa, where people had gathered.
Dozens were killed in a blast at the Gothic-style St Sebastian church in Katuwapitiya, north of Colombo. Police said they suspected it was a suicide attack.