The Sri Lankan government believes a local Islamist extremist group called National Thowheeth Jama’ath (NTJ) was behind deadly suicide bomb blasts 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.

Meanwhile, according to a report in Reuters, Sri Lankan President Maithripala Sirisena will declare nationwide emergency from midnight on Monday following the blasts.

Earlier, the Government Analyst’s Department had said that a total of seven suicide bombers carried out a series of eight devastating blasts that tore through churches and luxury hotels in Sri Lanka on Easter Sunday, killing 290 people in the country’s worst terror attack.

The blasts targeted St Anthony’s Church in Colombo, St Sebastian’s Church in the western coastal town of Negombo and Zion Church in the eastern town of Batticaloa around 8.45 am (local time) as the Easter Sunday mass were in progress.

Explosions were also reported from three five-star hotels — the Shangri-La, the Cinnamon Grand and the Kingsbury in Colombo.

The death toll rose to 290 on Monday, including six Indians.

This was the biggest ever terror attack in the country since the end of the Sri Lankan civil war involving the LTTE and the Sri Lankan military.

Among the dead were at least 30 foreigners – all in Colombo. Reports suggest that the foreign nationals killed in attack include British, Dutch, Americans and Japanese among others.

Police have arrested 24 suspects till now in connection with attacks. However, no group has claimed responsibility for Sunday’s serial blasts.

(With agency inputs)