Even as Israeli forces pushed deeper into the Gaza Strip, unleashing intense artillery fire as they moved to demolish militants’ tunnels into Israel, several Hamas fighters slipped through one of the passages on Saturday and killed two Israeli soldiers on patrol before being driven back, the Israeli military said.

The infiltration, the second in three days, was the latest indication that the tunnel network from Gaza into Israel is far more extensive than previously publicly known. The attack seemed to send a message that Hamas was undeterred in its efforts to launch assaults on Israel, and it could spur a new escalation: Israel cited an earlier infiltration on Thursday as the immediate catalyst for its ground invasion of Gaza.

The military said the infiltrators on Saturday had planned “a lethal attack” in a nearby community, but did not name the town. Hamas media also reported that fighters had “crossed enemy lines” and engaged Israeli forces. […]