Sri Lankan President Maithripala Sirisena declared the state of emergency "in the interest of public security, the preservation of public order and the maintenance of supplies and services essential to the life of the community," according to a special gazette notification.

The declaration gives security forces special powers, including the right to search and arrest individuals.

On Monday, authorities found several more bombs around the country.

Eighty-seven bomb detonators were found at a bus depot in Colombo. Officials declined to say whether they were linked to the attacks.

Adding to the tension, three unexploded bombs blew up inside a van parked near one of the stricken churches as police were trying to defuse them, sending pedestrians fleeing in panic. No injuries were reported.

Earlier on Monday, a pipe bomb with 50 kilograms of explosives was found and defused late Sunday on a road to the international airport, said Air Force Group Captain Gihan Seneviratne. He said it was powerful enough to have caused damage in a 400-metre radius.

The state of emergency took effect after Sri Lanka's Security Council decided to give sweeping powers to security forces and police carrying out search operations and investigations. Similar powers were given to the police and security forces when they were fighting Tamil rebels in the north and eastern parts of the country in a conflict that ended in 2009.

"I feel that the emergency powers should be given at least for a few days in order to carry out security operations," Army commander Lt. Gen. Mahesh Senanayake told journalists.

Also Monday, Sirisena appointed a Supreme Court judge-led team to investigate the attacks.

Supreme Court judge Vijith Malalgoda will head the team, which will also include former inspector general of police NK Illangakoon and ex-administrative officer Padmasiri Jayamanna. The team is expected to report back in two weeks.

The international police organization Interpol has also sent a team of experts to Sri Lanka at the request of local authorities to support ongoing investigations into the bombings, Interpol said in a statement Monday.

The experts include those with an expertise in crime scene examination, explosives, counterterrorism and victim identification.

"Information to help identify individuals linked to these attacks could come from anywhere in the world, which is where Interpol's global network and databases can prove vital, especially for officers on the ground," the statement read.

The move to expand investigations into the attacks comes amid government allegations that police had advanced information about possible Islamist suicide attacks in churches but failed to act on it.

Government spokesman and Health Minister Rajitha Senaratne told a news conference that an organization named National Thowheeth Jamath is believed to be responsible for Sunday's attacks, which were carried out by seven suicide bombers.

There has been no claim of responsibility.

"We believe there was international support for this type of attack. Such attacks cannot be carried out without such support," Senaratne said. "If we had prior information, we could have taken precautions. The inspector general of police should resign over this."

Sirisena, who also serves as defense minister, is responsible for the police and hails from a different party than Prime Minister Ranil Wickremesinghe.

Wickremesinghe and Sirisena are in an uneasy coalition government after the president unexpectedly sacked the prime minister in October. His position was restored by the courts after a 52-day political crisis.

Late Monday, police commandos defused an explosive device and discovered 87 detonators in two separate locations in the capital, police said.

The explosive device was found inside a vehicle parked close to the location where one of the suicide bomb attacks was carried out - a church in Kotahena, a suburb of the capital.

The 87 detonators were found close to a main bus stand in the capital.

Police have arrested at least 24 people in connection with Sunday's bomb blasts.

Government Analyst N Welianga told reporters the three attacks on churches and three others on hotels in the capital were carried out by suicide bombers.

The Defense Ministry was probing whether two bombers were involved in one of the hotel attacks, which would mean that a total of seven suicide bombers were involved in the coordinated blasts.

Police spokesman Ruwan Gunasekara said that the individuals arrested, all locals, were being questioned by the Criminal Investigation Department.

Gunasekara said they have found that one suicide bomber's wife and their two children and a relative were killed Sunday after someone set off an explosive as police were trying to search their place.

The death toll increased overnight as more victims died in hospital and several other bodies were discovered.

A dusk-to-dawn curfew imposed throughout the Indian Ocean island nation was lifted Monday morning. Schools and universities were expected to remain closed and the stock exchange suspended trading until further notice.

The curfew was re-imposed from 8 p.m. Monday until 4 a.m. Tuesday.

Authorities have located a van - believed to have transported the bombers - and the house where they stayed on the outskirts of Colombo.

Late Sunday, a home-made bomb was found inside a plastic pipe close to the airport and defused, a spokesman for the Air Force said.

The explosions took place during busy Easter services at Christian churches in the cities of Negombo, Batticaloa and Colombo and in three five-star hotels in the capital.

The bodies of 31 foreign nationals who were killed in the bombings have been identified, while 14 foreigners are unaccounted for and feared dead, the Foreign Ministry says.

Black and white flags have been put up in most parts of the country to mourn the deaths, with some of the funerals due to take place later in the day.

McClatchy