IS claims responsibility for Sri Lanka bombings 'to avenge 50 dead in NZ mosque massacre'
Islamic State (IS) has claimed responsibility for the Sri Lankan bombings in which 321 people died.
The claim came shortly after Sri Lankan authorities blamed the Easter Sunday bombings on two local Islamist groups.
Officials said both groups had suspected links to foreign militants.
The coordinated attacks are believed to have been in retaliation for last month's mosque massacre in New Zealand in which 50 people died.
It has been claimed that Sri Lanka was warned by India hours before the bombings that attacks by Islamists were imminent. It was not clear what action, if any, was taken.
Sri Lanka's prime minister, Ranil Wickremesinghe, said investigators were making progress in identifying the perpetrators of the attacks.
"We will be following up on IS claims," he said. "We believe there may be some links."
The government said at least seven suicide bombers were involved in the weekend attacks, which targeted three churches and three luxury hotels.
In a statement, IS named what it said were the seven bombers.
It gave no further evidence to support its claim of responsibility.
Earlier, junior defence minister Ruwan Wijewardene said two local Islamist groups - the National Thawheed Jama'ut and Jammiyathul Millathu Ibrahim - were responsible for the bombings in which more than 500 people were injured.
The first six blasts came within 20 minutes of each other as the hotels served breakfast and the churches celebrated Easter.
There were two more explosions - at a downmarket hotel and a house in a suburb of the capital, Colombo - later in the day.
Of the 321 people killed, 38 were foreigners. Forty-five children were among the dead.
Footage is said to show one of the bombers pat a child on the head before entering St Sebastian's Church in Katuwapitiya, north of Colombo, where dozens were killed.
Wijewardene said investigators believe revenge for the New Zealand attacks was the motive.
Sunday's blasts brought a shattering end to a relative calm that had existed on the Buddhist-majority island since civil war ended 10 years ago.
More than 1,000 mourners gathered yesterday for a mass funeral at St Sebastian's Church in the coastal city of Negombo, just north of Colombo.
More than 100 parishioners were killed there.