Senior U.S. officials have told their Israeli counterparts the Biden administration would support Israel going after high-value Hamas targets in and underneath Rafah — as long as Israel avoids a large-scale invasion that could fracture the alliance.

The Biden administration is still grappling with what kind of Israeli military operation it can accept in Rafah, with U.S. officials knowing full well Israel wants to eliminate Hamas’ four battalions in the southern Gaza city on Egypt’s border. President Joe Biden’s “red line,” which he drew over the weekend, is that Israel should no longer pursue a campaign without credible civilian protection plans in place.

But Israel’s military still has yet to produce such a plan. Two Israeli officials said the military is still developing ideas to ensure the safety of 1.3 million Palestinians in and around the city, many of whom fled there to avoid the war.