Some Israeli military officials have privately concluded that Palestinians in Gaza face widespread starvation unless aid deliveries are restored within weeks, according to three Israeli defense officials familiar with conditions in the enclave.

For months, Israel has maintained that its blockade on food and fuel to Gaza did not pose a major threat to civilian life in the territory, even as the United Nations and other aid agencies have said a famine was looming.

But Israeli military officers who monitor humanitarian conditions in Gaza have warned their commanders in recent days that unless the blockade is lifted quickly, many areas of the enclave will likely run out of enough food to meet minimum daily nutritional needs, according to the defense officials. They spoke on the condition of anonymity to share sensitive details.

Because it takes time to scale up humanitarian deliveries, the officers said that immediate steps were needed to ensure that the system to supply aid could be reinstated fast enough to prevent starvation.

The growing acknowledgment within part of the Israeli security establishment of a hunger crisis in Gaza comes as Israel has vowed to dramatically expand the war in Gaza to destroy Hamas and bring back the remaining hostages — twin aims that more 19 months of war have yet to achieve. On Tuesday, Prime Minister Benjamin Netanyahu was defiant, and said the military would resume fighting in the coming days “in full force to finish the job” and “eliminate Hamas.”

Mr. Netanyahu’s statement came on the same day that President Trump landed in Saudi Arabia, as part of his first major foreign trip since his re-election. Mr. Trump, however, is not visiting Israel, underscoring a growing divide between two leaders who increasingly disagree on some of the most critical security issues facing Israel.