Sri Lanka President Maithripala Sirisena said it is “quite possible” a foreign mastermind was behind the Easter Sunday bombings, claimed by ISIS, telling the terror group to “leave my country alone,” according to a report.

More than 250 people were killed, including 40 nationals, in the April 21 suicide bombings, which struck churches and hotels within minutes of each other.

Sirisena also warned it may be possible that ISIS has launched a “new strategy” by beginning to target smaller countries, Sky News reported Wednesday.

He told the news outlet that authorities are aware of “a small group” of Sri Lankans who have traveled abroad to receive training from the militant group over the past decade.

Sirisena added that analysis of explosives and devices retrieved by authorities suggests the bombs used in the attacks were manufactured locally.

The president said there was no evidence that one of the suspects, Abdul Lathief Jameel Mohammed, was radicalized in England, where he studied between 2006 and 2007 before taking postgraduate classes in Australia and eventually resettling in Sri Lanka.

On Tuesday, a government source told Reuters that security forces in the Buddhist-majority nation had been ordered to remain on high alert because the militants were expected to try to strike again, before the holy month of Ramadan, which starts Monday.

Authorities suspect members of two previously little-known groups — National Thawheedh Jamaath and Jammiyathul Millathu Ibrahim — of carrying out the attacks.

On Monday, the media network of ISIS published a video message purporting to come from its leader, Abu Bakr al-Baghdadi, which would be his first appearance since declaring the jihadists’ now-defunct “caliphate” five years ago.

In the clip, a bearded man with Baghdadi’s appearance says the bombings in Sri Lanka were ISIS’ response to losses in its last territorial stronghold of Baghouz in Syria.