Sri Lankan Prime Minister Ranil Wickremesinghe has said that his government will, if necessary, seek Pakistan's help to trace the terrorists involved in the recent Easter Sunday bombings and eliminate them.

In an exclusive interview with the Hindustan Times published on Friday, Wickremesinghe pointed out that Pakistan had, in the past, "fully supported Sri Lanka's war on terror".

He added: "If necessary, we will seek their help to trace the terrorists and eliminate them. I see this tragic event as further strengthening the trust that exists between our countries and increasing cooperation."

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Prime Minister Wickremesinghe said that although Sri Lanka is investigating the possibility of foreign links in the attack, there is no evidence yet to suggest that any particular country has backed the terrorists involved in the string of bombings that left approximately 250 people dead.

"All the countries in our region are faced with the same threats [...] Even the best of defences can sometimes be breached by ruthless terrorists, as we have seen time and again, all over the world. Our intelligence has worked with their counterparts [foreign intelligence agencies] abroad. But this is the first time that global terrorism has struck Sri Lanka. This is a new experience for us and we will work with our international allies to apprehend all the perpetrators," he vowed.

The Sri Lankan premier, when asked about anti-Muslim sentiment in the country, said there had been a marked improvement since 2012-2014, when the minority community was "under pressure". He noted that since 2015, "anti-Muslim sentiment was not allowed to raise its head".

"There was only one unfortunate incident in Kandy, which was brought under control. They have been patient in the face of these provocations, and I must commend their political leaders for maintaining inter-religious harmony," he said.

Read more: Sri Lankan Muslim Council calls for protection of Buddhist sites threatened by IS

"But again, the wave of anti-Muslim sentiment spreading across the liberal world and our region, has had some impact on Sri Lanka as well. We must provide constitutional guarantees to every community to coexist within one Sri Lanka," he asserted.

Sri Lankan officials revised the death toll from the Easter Sunday bombings down by about 100 on Thursday, blaming the difficulty in identifying body parts at bomb scenes for the earlier inaccurate number. The new official figure was 253, down from an earlier 359, Deputy Defence Minister Ruwan Wijewardene said, blaming inaccurate data provided by morgues for the discrepancy.

Government officials have acknowledged a major lapse in the sharing of intelligence information. Lakshman Kiriella, the leader of parliament, said senior officials had deliberately withheld the intelligence about possible attacks. The defence secretary, Hemasiri Fernando, resigned over the failure to prevent the attacks yesterday, although he insisted that the authorities had been acting in response to intelligence tips from India warning of imminent attacks. He said he had resigned to take responsibility for institutions he ran, but said there had been no failure on his part.

The militant Islamic State group has claimed responsibility for the attacks. It released a video that showed eight men, all but one with their faces covered, standing under a black Islamic State flag and declaring their loyalty to its leader, Abu Bakr Al-Baghdadi. The government said there were nine suicide bombers, eight of whom had been identified. One was a woman.

Authorities have focused their investigations on international links to two domestic Islamist groups — National Thawheed Jama'ut and Jammiyathul Millathu Ibrahim — they believe carried out the attacks.

A picture has emerged of a group of nine well-educated, home-grown suicide bombers. Two were brothers, sons of a wealthy spice trader, a source close to the family said.

At least 76 people, including several foreigners, have been rounded up since Sunday, but police on Thursday for the first time identified seven people they were looking for and appealed to the public for help in finding them.

Photographs, apparently casual snapshots, posted with a wanted notice showed young bearded men, one with a Muslim cap, and three young women, all with headscarves.

Meanwhile, fears are growing of a surge of communal tension. Out of Sri Lanka's total population of around 22 million, 70pc are Buddhist, 12.6pc Hindu, 9.7pc Muslim, and 7.6pc Christian, according to the country's 2012 census.

Muslims have fled the Negombo region on Sri Lanka's west coast since scores of worshippers were killed in the bombing of the St. Sebastian church there on Sunday. Hundreds of Pakistani Muslims have left the port city, crammed into buses, after threats of revenge.