SRI Lanka’s president has asked for the resignations of the defence secretary and national police chief over the Easter Sunday bombings that killed more than 350 people.

The move marks a dramatic internal shake-up after security forces shrugged off intelligence reports warning of possible attacks. It was not immediately clear who would be replacing them, but President Maithripala Sirisena said during a televised speech that he planned to change the head of the defence forces within 24 hours.

Daesh has claimed responsibility for the attacks, which targeted Christians worshipping in three churches and people at three luxury hotels. Authorities remain unsure of the group’s involvement, although many suspect experienced foreign militants were advising, funding or guiding the attackers.

Sri Lanka’s junior defence minister has blamed breakaway members of two obscure local extremist Muslim groups, and said many of the suicide bombers were highly educated and came from well-off families.

“Their thinking is that Islam can be the only religion in this country,” Ruwan Wijewardene told reporters.

“They are quite well-educated people,” he said, adding that at least one had a law degree and some may have studied in the UK and Australia.

Leaders have vowed to overhaul the country’s security apparatus after acknowledging that some intelligence units were aware of possible attacks before the Easter bombings.

Government statements about the attacks have been confused and sometimes contradictory, with police spokesman Ruwan Gunasekara telling reporters there were nine suicide bombers, two more than officials said one day earlier.

One of the additional suicide bombers was the wife of another bomber, Gunasekara said.

The woman, two children and three policemen died in an explosion as authorities closed in on her late on Sunday. The ninth suicide bomber has not been identified, although two more suspects were killed in a later explosion on the outskirts of Colombo.

Gunasekara said 60 people have been arrested so far. A team of FBI agents and US military officials was helping in the investigation, US ambassador Alaina Teplitz said. Officials say all of the main suicide bombers were Sri Lankan.

“We are conducting investigations at the moment to see if there is any direct link to any international organisations,” Wijewardene said.

Daesh’s Aamaq news agency released an image it said showed the attackers’ leader standing amid seven others with covered faces. It provided no other evidence for its claim of

responsibility. The group, which has lost all the territory it once held in Iraq and Syria, has made a series of unsupported claims of responsibility for various attacks around the world.

Sri Lankan authorities had earlier blamed a local extremist group, National Towheed Jamaar, whose leader, alternately named Mohammed Zahran or Zahran Hashmi, became known to Muslim leaders three years ago for his incendiary online speeches.

Yesterday, Wijewardene said the attackers had broken away from National Towheed Jamaar and another group, which he identified only as JMI. Teplitz declined to discuss whether US officials knew about National Towheed Jamaar or its leader before the attack.

“If we had heard something, we would have tried to do something about this,” Teplitz said.

The country has been on heightened alert since the attacks, with police setting off a series of controlled explosions of suspicious objects. No more bombs were found yesterday.

Also yesterday, Wijewardene edged away from Tuesday comments that the bombings were retaliation for the March 15 mosque shootings in Christchurch, New Zealand, that killed 50 people, saying there was no direct evidence of that.