An initial probe into deadly suicide bomb attacks in Sri Lanka that killed more than 300 people shows it was "retaliation for Christchurch," the country's deputy defence minister said Tuesday.

Two women mourn during a funeral service for bomb blast victims at St Sebastian's Church in Negombo on April 23, 2019, two days after a series of bomb attacks targeting churches and luxury hotels in Sri Lanka. (Photo: AFP)

"The preliminary investigations have revealed that what happened in Sri Lanka (on Sunday) was in retaliation for the attack against Muslims in Christchurch," state minister of defence Ruwan Wijewardene told parliament.

Fifty people were killed in shooting attacks on two mosques in the New Zealand city of Christchurch on March 15.