Seven suicide bombers believed to be members of an Islamist extremist group carried out a series of devastating blasts that tore through churches and luxury hotels in Sri Lanka on Easter Sunday, killing 290 people and wounding 500 others in the country's worst terror attack, authorities said on Monday.
A state of emergency was declared from midnight Monday after a crucial meeting of the National Security Council chaired by President Maithripala Sirisena.
No group has claimed responsibility for Sunday's attacks, but police have so far arrested 24 people - mostly members of the same group - in connection with the blasts that also killed six Indian nationals.
Police said that 9 out of the 24 arrested for involvement in the blasts were ordered to be remanded by the Colombo magistrate's court till May 6.
Government's spokesman Rajitha Senaratne said local Islamist extremist group called the National Tawheed Jamath (NTJ) is suspected of plotting the blasts that struck three churches when the Easter Sunday mass was in progress and three five-star hotels.
"All suicide bombers involved in the blasts are believed to be Sri Lankan nationals," said Senaratne, who is also the Health Minister.
Speaking at a press conference here, Senaratne said the government was investigating whether the group had "international support".
"There may be international links to them," he added.
The Government Analyst's Department was quoted as saying by the Sunday Times that the blasts at the Shangri-La, Kingsbury and Cinnamon Grand hotels, and also at St Anthony's Church in Kotahena, St. Sebastian's Church in Katuwapitiya and the Zeon Church in Batticaloa have been identified as suicide bombings.
"A total of seven suicide bombers had carried out these explosions," the department said.
Around 290 people, including six Indians, were killed in the blasts that left more than 500 others injured, police spokesman Ruwan Gunasekera said.
He said that 24 arrested suspects have been transferred into the custody of the Criminal Investigations Department (CID) for further investigations.
The National Security Council (NSC) has announced plans to impose a "conditional state of emergency" from midnight, said a statement from the president's media unit.
It said the measures would target terrorism and would not limit freedom of expression.
"These will be limited to counterterrorism regulations. This is being done to allow the police and the three forces to ensure public security," the statement said.
The government has also declared Tuesday as a national day of mourning.
President Sirisena has appointed a three-member committee to conduct investigations. The committee will submit its report to the President within two weeks.
Health Minister Senaratne said the Chief of National Intelligence had warned the Inspector General of Police (IGP) regarding the probable attacks before April 11.
"On April 4, international intelligence agencies had warned of these attacks. The IGP was informed on April 9," he said.
He demanded the resignation of police chief Pujith Jayasundera in view of the major security lapse.
Prime Minister Ranil Wickremesinghe said that an investigation must be launched as to why intelligence reports of the attack was not taken seriously.
Rauff Hakeem, a government minister and the leader of the main Muslim party - Sri Lanka Muslim Congress, said that it was lamentable that no preventive action had been taken despite the inputs.
"They have known this..., the names have been given, identified, but (they) took no action," he added.
Two Sri Lankan Muslim groups - the All Ceylon Jamiyyathul Ulama and the National Shoora Council - have condemned the blasts and demanded that all culprits be brought to book.
Meanwhile, as many as 87 bomb detonators were found on Monday at the Central Colombo bus station in Pettah area. The police initially found 12 bomb detonators scattered on the ground. A further search revealed 75 more, a police statement said.
A safe house where the bombers had lived for nearly three months leading to the attacks was found in the south of Colombo suburb of Panadura.
Sri Lanka Air Force said it found an improvised explosives device along a road leading to the departure terminal at the Colombo international airport Sunday night and safely defused it.
"It was a crude six-foot pipe bomb that was found by the roadside," an air force spokesman said.
On Sunday, External Affairs Minister Sushma Swaraj identified three Indians as Lakshmi, Narayan Chandrashekhar and Ramesh who died in the blasts.
The Indian High Commission Monday confirmed the deaths of two more individuals in the blasts - K G Hanumantharayappa and M Rangappa.
Kerala Chief Minister Pinarayi Vijayan Sunday identified a Keralite, P S Rasina (58), among those killed in the blasts.
Four of them died in the Colombo National Hospital while the bodies of two Indians who succumbed to their injuries from the blast at the Shangri-La Hotel has been sent for autopsy, the National Hospital spokesperson said.
Sri Lanka Monday ordered a new night-time curfew following the multiple attacks.
The blasts shattered a decade of peace in the island nation since the end of the brutal civil war with the LTTE.
The civil war ended with the defeat of the Tamil Tigers, who had fought for 26 years for an independent homeland for the minority ethnic Tamils. The war is thought to have killed between 70,000 and 80,000 people.