Israeli Prime Minister Benjamin Netanyahu has ordered the Israel Defense Forces to come up with a "dual plan" to evacuate the civilian population in Rafah in the southern Gaza Strip before "disbanding" Hamas battalions allegedly located there, according to his office.

"It is impossible to achieve the war objective of eliminating Hamas and leaving four Hamas battalions in Rafah," Netanyahu's office said in a statement Friday. "On the other hand, it is clear that a massive operation in Rafah requires the evacuation of the civilian population from the combat zones."

"That is why the Prime Minister directed the IDF and the defense establishment to bring to the cabinet a dual plan for both the evacuation of the population and the disbanding of the battalions," the office added.

Rafah is the southernmost governorate of Gaza, where more than half of the 2.3 million population has sought refuge after being displaced from their homes amid Israel's military offensive in the Hamas-ruled enclave, according to the United Nations. The U.N. and other aid organizations have expressed concern over where civilians would go if Rafah, which the IDF previously designated a safe zone, becomes the next target in Israel's war against Hamas.

-ABC News' Jordana Miller and Morgan Winsor

The United Nations International Children's Emergency Fund on Friday urged Israel and Hamas to refrain from escalating fighting in Rafah, the southernmost governorate in the war-torn Gaza Strip, where more than a million people have sought refuge after being displaced from their homes.

"UNICEF is urgently calling on the parties to refrain from military escalation in Rafah Governorate in Gaza where over 600,000 children and their families have been displaced -- many of them more than once," UNICEF Executive Director Catherine Russell said in a statement. "An escalation of the fighting in Rafah, which is already straining under the extraordinary number of people who have been displaced from other parts of Gaza, will mark another devastating turn in a war that has reportedly killed over 27,000 people -- most of them women and children."

"Thousands more could die in the violence or by lack of essential services, and further disruption of humanitarian assistance," she added. "We need Gaza's last remaining hospitals, shelters, markets and water systems to stay functional. Without them, hunger and disease will skyrocket, taking more child lives."

ABC News' Nasser Atta, Edward Szekeres and Morgan Winsor

The U.S. would not support Israel sending its military into the southern Gaza city of Rafah -- where many Gaza residents have fled for safety -- if Israel does not consider the impact to civilians, White House national security spokesperson John Kirby told reporters.

"More than a million Palestinians are sheltering in and around Rafah. That's where they were told to go," Kirby said. "The Israeli military has a special obligation, as they conduct operations there or anywhere else, to make sure that they're factoring in protection for civilian life -- particularly civilians that were pushed into southern Gaza by operations further north."

"Given the circumstances and the conditions there that we see right now, we think a military operation at this time would be a disaster for those people," Kirby said.

Kirby noted that the U.S. has not seen any Israeli plans "that would convince us that they are about to or imminently going to conduct any kind of major operations in Rafah."

-ABC News’ Fritz Farrow

State Department deputy spokesperson Vedant Patel acknowledged Thursday that the U.S. was aware of reports that two American citizens had been detained by the Israel Defense Forces in Gaza but said he couldn’t share anything more.

"We have no higher priority than the safety and security of American citizens overseas," Patel said. "We are aware of these reports, and we are currently seeking additional information. But I don't have any additional information to share and would not be able to at this point, given the privacy considerations."

White House national security spokesperson John Kirby told reporters, "Obviously, this is the kind of thing to take very seriously. So, we'll be talking to our Israeli counterparts and trying to get information, more context here, about what happened."

-ABC News’ Shannon Crawford