The Islamic State claim on its Aamaq news agency backed Sri Lankan government assertions the attackers had international terrorist help and came as more details of security blunders prior to the bombing were disclosed.

Indian intelligence officials issued detailed warnings to Sri Lankan authorities that Hashmi and his brother were plotting attacks two weeks earlier and even named a suspected bombmaker. Delhi repeated its alert only hours before the bombs went off.

The Sri Lankan Muslim community had also repeatedly told the government over the past three years that Hashmi had been using online sermons to preach hate against Buddhists, Hindus and Christians.