Islamic terrorists are feared to be plotting Sri Lanka-style massacres at other popular tourist destinations, intelligence officials have warned.

Jihadi fighters fleeing Iraq and Syria after the fall of ISIS are now able to concentrate on plotting devastating attacks with radicals overseas, according to the UK’s Sunday Telegraph.

Intelligence sources told the paper that the devastation in Sri Lanka — where at least 250 were killed — will strengthen the resolve to further target popular hotspots packed with tourists.

The dire warnings come as all Catholic Sunday Masses in Sri Lanka have also been suspended until further notice following the Easter Sunday attacks.

“It’s grim to say so, but we should expect more attempts at attacks like these more regularly for the foreseeable future,” warned Aymenn Jawad Al-Tamimi, a researcher who tracks ISIS.

“Sri Lanka was not a one-off. If anything, it was a test run.”

Well-placed sources told the paper that India, the Maldives and east African resorts in Kenya and in Tanzania are most vulnerable.

“The change in tactics is a big worry,” one intelligence source told the paper. “When they were running a de facto state that also meant running things like a health service and all that entails. That took up a lot of their time.

“But now they are not doing that they have a lot of time to push out their propaganda and they do that by carrying out attacks.”

A second source also warned that the end of ISIS’ stronghold in Syria meant that terrorists are “dispersing around the world and seeking to carry out attacks.”