The extremist Islamic State group’s branch in Egypt’s Sinai Peninsula has taken a simmering dispute with the Palestinian Hamas group based in nearby Gaza to new levels, releasing a 22-minute video in which it calls on its followers to attack the group and shows the execution of a man it said was a collaborator.

Analysts say the escalation has the potential to destabilize an already fragile security situation in Gaza, the Palestinian enclave that Hamas has controlled for the past decade.

“Never surrender to them. Use explosives, silenced pistols, and sticky bombs. Bomb their courts and their security locations, for these are the pillars of tyranny that prop up its throne,” says the knife-wielding narrator of the video, according to a translation distributed by the SITE Intelligence Group, which monitors extremist websites.