Sri Lankan Prime Minister Ranil Wickremesinghe spoke to NDTV in an exclusive interview.

Highlights A series of eight explosions killed over 300 people in Sri Lanka

"Had Intelligence, was not conveyed down the line": Ranil Wickremesinghe

Added investigators were in touch with China, Pakistan and other nations

India had shared intelligence inputs with Sri Lanka but there was a lapse in how the country handled it, Lankan Prime Minister Ranil Wickremesinghe told NDTV in an exclusive interview in Colombo on Tuesday, three days after a terrorist attack killed more than 300 people and injured over 500.

"India gave us the intelligence but there has been a lapse on how we acted on that... intelligence was not conveyed down the line," Mr Wickremesinghe said, adding that Sri Lankan investigators were in touch with several countries, including China and Pakistan, as they probed the strike.

A series of eight explosions had hit churches and hotels on Easter Sunday in an attack that was claimed by terror network ISIS on Tuesday. Sri Lanka had earlier named a local Islamist group, National Thowheeth Jama'ath, as the chief suspect, for the incident act that has sparked international outrage. The suicide strikes sent shockwaves through the island state that has been relatively peaceful since a civil war ended a decade ago.

A statement on the ISIS's official al-Amaq news agency made the claim on the encrypted messaging app Telegram saying the suicide bombers were "fighters of the Islamic State". But it did not provide any evidence of its involvement.

Indian intelligence officers contacted their Sri Lankan counterparts two hours before the first attack to warn of a specific threat on churches, news agency Reuters reported quoting a Sri Lankan defence source and an Indian government source. Another Sri Lankan defence source said a warning came "hours before" the first strike, Reuters reported.

"So far it [those responsible] has been a group confined to Sri Lankan citizens but with foreign connections. This is why we have asked the assistance of some of the foreign agencies to trace the overseas involvement," Mr Wickremesinghe said.

"We have a good intelligence sharing system with India. It has been giving us the help we need. We also have got help from USA and UK. Our priority is to apprehend the terrorists. Until we do that, no one is safe," he said.

The Prime Minister said it was possible that the attacks were retaliation for the shooting last month at a mosque in the New Zealand city of Christchurch - a theory that has been voiced by one of his ministers. "But the planning took place before Christchurch," Mr Wickremesinghe said.

He dismissed that the attacks have frayed communal harmony in Sri Lanka. "It is individuals who work on these and it is not organised movement backed by Muslims. There is a certain amount of tension but that is natural in situation like this. We have to tackle it," he said.

He said Sri Lanka was confident of its critical tourism sector recovering from the setback. "We will be back on the scene. Not only us, Egypt has gone through this, Bali had been through it. It is unfortunate for the economy but tourism will recover... we have come through many such incidents of terror and war," Mr Wickremesinghe said.

(With inputs from agencies)