If there is one thing that stands out about the attacks in Indonesia on Sunday and Monday it is that they were carried out by two families — two sets of parents, who together with their own children undertook suicide attacks on four targets.

The head of the International Centre for Political Violence and Terrorism Research in Singapore, Rohan Gunaratna, said parents co-opting their own children to carry out attacks is a worrying new trend.

“This is not a one-off. We are likely to see more of these attacks,” he said.

Professor Gunaratna agreed that attacks by families are a new phenomenon in the Asia Pacific region, but said that families and couples have tried to use children in bombings in other parts of the world before.

What he thinks is significant about this development is that it shows that terrorists are able to radicalise whole families.

“This requires a family and community-oriented response to fight the threat,” he said.