The Biden administration will be requiring countries that receive weapons from the U.S. to provide "credible and reliable" written assurances to the State Department that they will use those weapons in accordance with the laws of war, according to a national security memorandum released Thursday.

The executive action applies globally to the more than 100 countries that currently receive American arms and aid and adds a new requirement that an annual report be sent to Congress.

The move comes as the Biden administration faces pressure from top Democratic lawmakers to limit civilian casualties in the Gaza Strip as Israel wages its fourth month of war against Hamas. The U.S. provides billions of dollars of military assistance to Israel each year, which some progressives, like independent Sen. Bernie Sanders, have argued, makes the U.S. complicit in civilian deaths.

The IDF has not disclosed how many civilians it estimated it has killed, but Hamas officials in Gaza say the death toll is nearing 28,000. However, Hamas statistics do not differentiate between civilian and combatant deaths. The IDF claims it has killed 9,000 fighters but did not disclose estimates of civilian casualties. CBS News producer Marwan alGhoul has reported firsthand accounts of hospitals filled with women and children injured in the fighting.

A senior administration official told CBS News that the new memorandum is not being issued because the White House believes that a country is currently violating these standards.

"This is an opportunity to be transparent with the American public [about] what the standards we require countries to adhere to are and how we go about obtaining assurances that they'll be met," the official said.

The memo requires written commitments from the more than 100 countries that receive U.S. weapons within 180 days. Those in active conflict, including Israel and Ukraine, must respond within 45 days. If the president doesn't receive those assurances, the U.S. can cut off assistance.

It also requires the secretaries of state and defense to provide a report to Congress on weapons or assistance provided to other countries within the next 90 days. The first report will include any assistance provided since Jan. 1, 2023.

An administration spokesperson told CBS News that the memo emerged in part from conversations with members of Congress who raised questions about existing standards and how the standards are enforced. Nineteen Democratic senators have pushed for an amendment in the national security supplemental bill being negotiated in Congress to require the use of U.S. supplemental aid to comply with U.S. international law.

"U.S. security assistance should always be used in line with our nation's interests and our values, including upholding international humanitarian law," Democratic Sen. Chris Van Hollen of Maryland said in a statement Thursday. "But until now, that was based on sentiment, not substance." Van Hollen is part of the group of lawmakers pressing the White House for more accountability on weapons and aid being sent to Israel.

Existing legislation known as the Leahy Law prevents the U.S. from providing weapons or funds for military assistance to groups when there is credible information indicating the groups have violated human rights. However, former Senator Pat Leahy, a Vermont Democrat, has said that past administrations have waived application of the law to the Israeli Defense Forces.

"What is being done to apply the Leahy law now? I don't know," Leahy told a Vermont news site, News & Citizen, in November. "I know past administrations have been too concerned to do it. It should apply to the Israeli Defense Forces, unless the administration, as many have, has waived it."

Lawmakers say Thursday's memorandum will strengthen the enforcement mechanisms.

"This will be the first time that we require recipients of U.S. military assistance to provide written assurances, promises, that they will comply with international humanitarian law," Van Hollen said.

The Biden administration has staunchly backed Israel's right to defend itself against Hamas after the militant group killed 1,200 Israelis and took roughly 240 people hostage in a bloody, surprise rampage last Oct. 7.

As the conflict's humanitarian conditions have deteriorated, however, Biden administration officials have pressed the Israeli government to limit the effect of its military operations on Gaza's civilian population.

Speaking from Tel Aviv Wednesday at the end of his fifth, multi-stop sweep of the Middle East, Secretary of State Antony Blinken made a public appeal for greater protections for the people of Gaza.

"Israelis were dehumanized in the most horrific way on October 7th. The hostages have been dehumanized every day since," Blinken said. "But that cannot be a license to dehumanize others."

On Friday, Israeli Prime Minister Benjamin Netanyahu announced that he had ordered his military to submit plans for a civilian evacuation of Rafah, where more than a million Palestinian civilians have sought refuge, ahead of an expected offensive aimed at destroying Hamas battalions there.

Officials from the White House and State Department have warned that an attack on Rafah without a plan for protecting the civilians sheltering there would be a "disaster." Blinken delivered a similar message directly to Netanyahu during their meeting in Jerusalem this week.

In a press conference Thursday, President Biden referred to Israel's actions in Gaza as "over the top."

Last month Van Hollen, returning from a visit to Rafah, told "Face the Nation" moderator Margaret Brennan that the president and secretary of state "had been right to insist on two things: a reduction in the unacceptable levels of civilian casualties, and much more cooperation when it comes to providing humanitarian assistance."

"We've not seen that," he said.