A foreign mastermind may have planned the Sri Lankan Easter Sunday bombings, President Maithripala Sirisena said. Sirisena also warned it may be possible Islamic State has launched a “new strategy” by targeting smaller countries, according to a TV report on Wednesday.

The April 21 attacks on hotels and churches in Sri Lanka killed more than 250 people, including 40 foreign nationals.

Authorities suspect members of two previously little-known groups – National Thawheedh Jamaath and Jammiyathul Millathu Ibrahim – of carrying out the attacks, although Islamic State has claimed responsibility.