A Sri Lankan minister says an initial investigation shows the deadly Easter Sunday attacks were carried out in retaliation for last month’s Christchurch mosque shootings.

Police announced they had arrested 40 people in connection with the coordinated bomb blasts, while the death toll from the attacks had risen to 321, with more than 500 injured.

Two domestic Islamist organisations, including National Thawheed Jama’ut, are said to be responsible for carrying out the suicide bombings at churches and hotels.

“The initial investigation has revealed that this was in retaliation for the New Zealand mosque attack,” Junior Minister for Defence Ruwan Wijewardene told Sri Lanka’s Parliament.

“It was done by National Thawheed Jama’ut along with JMI,” he said, referring to another local group, Jammiyathul Millathu Ibrahim.