Sri Lanka Blast: 290 were killed and 500 injured in 8 bomb blasts in Sri Lanka.

Highlights National Thowheeth Jama'ath believed behind attack that killed 290 people

Sri Lanka investigating if group had "international support"

Sri Lanka declares emergency from midnight, new curfew at 8 pm

The Sri Lankan government believes a local Islamist extremist group called the National Thowheeth Jama'ath (NTJ) was behind the deadly suicide bomb attacks that killed nearly 300 people, government spokesman Rajitha Senaratne said Monday.

Senaratne, who is also a cabinet minister, added that the government was investigating whether the group had "international support".

Documents seen by AFP show Sri Lanka's police chief issued a warning on April 11, saying that a "foreign intelligence agency" had reported NTJ was planning attacks on churches and the Indian high commission.

Not much is known about the NTJ, a radical Muslim group that his been linked to the vandalising of Buddhist statues.

A police source told AFP that all 24 people in custody in connection with the attacks belong to an "extremist" group, but did not specify further.

Meanwhile, the government said it will declare a nationwide emergency from midnight on Monday following the serial blasts.

"The government has decided to gazette the clauses related to prevention of terrorism to emergency regulation and gazette it by midnight," the Sri Lankan President Maithripala Sirisena's media unit said in a statement.

It said the measure would be confined to dealing with terrorism and would not impinge on freedom of expression.

The government also ordered a new night-time curfew as tensions remained high. The government information department said the curfew would run from 8:00 pm on Monday (local time) until 4:00 am on Tuesday.

SHARP RISE IN DEATHS

The number of deaths from the bomb blasts that ripped through churches and luxury hotels rose dramatically Monday to 290 - including dozens of foreigners - as police announced new arrests over the country's worst attacks for more than a decade.

More than 500 people were injured in the Easter Sunday assault that saw suicide bombers hit three high-end hotels popular with foreign tourists, and three churches, unleashing carnage in Colombo and beyond.

Two additional blasts were triggered as security forces carried out raids searching for suspects.

There was no immediate claim of responsibility, but police said Monday 24 people had been arrested.

Prime Minister Ranil Wickremesinghe said an investigation would look into "why adequate precautions were not taken".

President Maithripala Sirisena, meanwhile, who was abroad at the time of the attacks, returned Monday and was chairing a security council meeting, his office said.

MEMORIES OF CIVIL WAR

Ethnic and religious violence has plagued Sri Lanka for decades, with a 37-year conflict with Tamil rebels followed by an upswing in recent years in clashes between the Buddhist majority and Muslims.

Dilip Fernando, who could not get into St Sebastian's because the church was already packed when he arrived, said the Christian community would not be intimidated.

"We are not afraid. We won't let the terrorists win, no way," the 66-year-old told AFP outside the devastated building.

Two leading Muslim groups issued statements condemning the attacks, with the All Ceylon Jamiyaathuul Ulama, a council of Muslim theologians, urging the "maximum punishment for everyone involved in these dastardly acts."

For many, the blasts stirred painful memories of Sri Lanka's civil war, when bomb attacks were a frequent occurrence.

"The string of blasts brings back memories of the time when we were afraid to go in buses or trains because of parcel bombs," said Malathi Wickrama, a street sweeper in Colombo.

In total, three churches in Colombo, Negombo and the east-coast town of Batticaloa were attacked, along with three luxury hotels in the capital.

A manager at the Cinnamon Grand, near the prime minister's official residence in Colombo, said a suicide bomber blew himself up at a breakfast buffet in the hotel restaurant.

"He came up to the top of the queue and set off the blast," the manager said.

Two further blasts happened as police staged raids looking for suspects. At least three police officers were killed in one raid.

The attacks drew global condemnation, including from US President Donald Trump and the pope.

Premier Wickremesinghe urged people to "hold our unity as Sri Lankans" and pledged to "wipe out this menace once and for all".

The archbishop of Colombo, Malcolm Ranjith, described the attackers as "animals" and called on authorities to "punish them mercilessly".

Embassies in Colombo warned foreign nationals to stay inside and there were chaotic scenes at Colombo airport.

(With inputs from AFP and Reuters)