Sri Lanka President Maithripala Sirisena has told the BBC that he believes the Islamic State (IS) group chose to mount attacks in his country to show they still exist.

Police in Sri Lanka have blamed two local Islamist groups for the Easter Sunday bombings, but acknowledged that they must have had support from groups abroad. IS has said it was behind the suicide attacks, which killed more than 250 people.

Mr Sirisena also told the BBC's Secunder Kermani that he would not resign despite criticism that the government failed to act on warnings.