US officials expect the current phase of Israel’s ground invasion of Gaza targeting the southern end of the strip to last several weeks before Israel transitions, possibly by January, to a lower-intensity, hyper-localized strategy that narrowly targets specific Hamas militants and leaders, multiple senior administration officials tell CNN.

But as the war enters this new ground phase in the south, the White House is deeply concerned about how Israel’s operations will unfold over the next several weeks, a senior US administration official said. The US has warned Israel firmly in “hard” and “direct” conversations, they said, that the Israeli Defense Forces cannot replicate the kind of devastating tactics it used in the north and must do more to limit civilian casualties.

The US has conveyed to Israel that as global opinion has increasingly turned against its ground campaign, which has killed thousands of civilians, the amount of time Israel has to continue the operation in its current form and still maintain meaningful international support is quickly waning.

In perhaps the most direct public warning to date, Defense Secretary Lloyd Austin admonished Israel that it can “only win in urban warfare by protecting civilians.” Speaking at the Reagan National Defense Forum over the weekend, Austin said US support for Israel is “not negotiable”, but he said Israel risks replacing a “tactical victory with a strategic defeat” if it did not do more to prevent civilian deaths.

Almost 16,000 Palestinians have been killed since Israel began its campaign in October, following Hamas’ terror attack on Israel on October 7, according to the Hamas-run Gaza Ministry of Health. Israel believes it has killed “several thousand” Hamas militants, an Israeli official said.