On a recent surveillance patrol, Israeli soldiers watched as a squad of Hamas militants approached the tense border between Gaza and Israel. But the commandos weren’t there to attack, but rather to block rogue militants seeking to launch rockets into Israel, an Israeli commander said.

Such patrols, confirmed by Hamas, are aimed at stanching a series of attacks by extremists aimed both within and outside the enclave that the Islamist group runs. Still, some attacks are occurring in any case, and Israeli and Palestinian officials fear that if unchecked, they may threaten a fragile cease-fire with Israel that has held since a bloody 50-day conflict ended in August.

“They are trying to embarrass Hamas,” said Mkhaimar Abusada, a political scientist in Gaza City, referring to the extremists. “The aim is to destabilize the cease-fire. Hamas is trying to maintain the cease-fire.” […]