Sri Lankan authorities were warned of possible terror attacks on Christian churches more than two weeks before the wave of bombings that left 290 people dead and more than 500 injured.

International intelligence agencies warned that the little-known domestic terror group, National Thowfeek Jamaath, was planning attacks, cabinet spokesman Rajitha Senaratne said at a media conference late Monday.

Mr Senaratne said that the warnings were not passed on to Prime Minister Ranil Wickremesinghe or his cabinet.

Mr Wickremesinghe acknowledged that security services had been “aware of information” but had not acted on the information.

News of the warning came as officials revealed the bombings were carried out with the support of an international network.

Meanwhile authorities found several more bombs around the country, according to UK Reuters.

Eighty-seven bomb detonators were found in Colombo – 12 scattered at Colombo’s main bus depot and another 75 at a garbage dump in the same area. Officials declined to say whether they were linked to the attacks.

Australian business manager Manik Suriaaratchi and her 10-year-old daughter, Alexandria, died in an explosion at Negombo, on the west coast of the country, where they were attending an Easter Sunday church service.

Ms Suriaaratchi was with her daughter in the church while her husband was parking the car, SBS reported.

The family had previously lived in Australia, and Mrs Suriaaratchi had been managing director of investment company Omega Global.

Manik Suriaaratchi and her daughter Alexandria had been at an Easter church service when a bomb exploded. Photo: Facebook

The co-ordinated bombings of churches and luxury hotels were carried out by seven suicide bombers from National Thowfeek Jamaath, Health Minister Rajitha Senaratne said.

Police have arrested a further 24 people in a series of raids and the president’s office declared a state of national emergency.

Sri Lankan authorities said they knew where National Thowfeek Jamaath trained and had safe houses, but are yet to identify the suicide bombers.

On Monday, another blast rocked a street near a church in the capital, Colombo. Police were attempting to defuse explosives in a vehicle used by the attackers when it blew up. It is not yet known if anyone was hurt.

Sri Lanka’s Telecommunications Minister, Harin Fernando, said “serious action” needed to be taken over the ignored attack warning.

“Some intelligence officers were aware of this incidence. Therefore there was a delay in action,” he tweeted.

Some intelligence officers were aware of this incidence. Therefore there was a delay in action. What my father heard was also from an intelligence officer. Serious action need to be taken as to why this warning was ignored. I was in Badulla last night pic.twitter.com/ssJyItJF1x

— Harin Fernando (@fernandoharin) April 21, 2019

Cardinal Malcolm Ranjith, the Archbishop of Colombo, said the attacks could have been thwarted.

“We placed our hands on our heads when we came to know that these deaths could have been avoided. Why this was not prevented?” he said.

-with agencies