The death toll from the Easter Sunday bombings in Sri Lanka sharply rose to 359 on Wednesday, police said.

Police spokesman Ruwan Gunasekara also said Wednesday morning that 18 suspects were arrested overnight, taking the total to 58.

On Tuesday, the Islamic State or the ISIS had claimed responsibility for the deadly attacks without providing any major evidence.

Meanwhile, the country’s deputy defence minister Ruwan Wijewardene told parliament that an initial probe into deadly suicide bomb attacks in Sri Lanka revealed it was “retaliation for Christchurch.”

“The preliminary investigations have revealed that what happened in Sri Lanka (on Sunday) was in retaliation for the attack against Muslims in Christchurch,” he said on Tuesday.

Meanwhile, Sri Lanka on Tuesday had placed all police stations in Colombo on high alert as police were hunting for an unidentified container truck and a van, believed to be carrying explosives.

The first memorial services for the victims, among them dozens of foreigners, were being held Tuesday, hours after the government imposed a state of emergency and said an ISIS group was behind the violence.

Earlier on Monday, the Sri Lankan government said that it suspected a local Islamist extremist group called National Thowheeth Jama’ath (NTJ) to be behind the deadly suicide bomb blasts, adding that it 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.

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 government warned on Tuesday that several suspects armed with explosives were still at large.