The U.S. received information from the Israelis overnight that they believe shrapnel or something else from the strike ignited a fuel tank 100 meters away, which engulfed a tent, creating a massive fire, according to a U.S. official.

The U.S. does not have information to confirm or dispute that information. The U.S. is in the process of understanding what has happened, waiting for Israel to conduct its own investigation and determining what action to take next, according to the official.

The U.S. maintains that while they’ve warned about a major ground offensive in Rafah, that’s not what’s happening, according to the official.

-ABC News' Selina Wang

Commenting on the Rafah strike that killed 50 people, Hamas released a statement saying Israel’s attack on Rafah is like "the announcement of Netanyahu’s government’s defiance of international justice decisions," referring to the International Court of Justice’s decision last week ordering Israel to stop its operation in Rafah.

"The massacre committed in the areas where its considered safe area," Hamas leader Osama Hamdan said. "The timing of these murders during the last two days is like the announcement of Netanyahu's government's defiance of international justice decisions."

Israeli Prime Minister Benjamin Netanyahu called the strike on Rafah which killed at least 50 Palestinians Sunday, a “tragic mishap,” in a speech to Israel’s parliament, the Knesset, Monday.

"We are fighting with force in the north of the Gaza Strip, in its center, its south and in Rafah. In Rafah we have already evacuated about a million uninvolved residents and despite our best efforts not to harm the un-involved, unfortunately a tragic mishap happened last night. We are investigating the case and will draw the conclusions because this is our policy," Netanyahu said.

-ABC News' Ellie Kaufman

At least 50 people have been confirmed dead in Israel's strike on Rafah, with a number of victims are still under the rubble, the Gaza Health Ministry said in a statement Monday. Ambulance and civil defense crews cannot reach them the victims, the statement noted.

Since Oct. 7, 36,050 people have been killed in Gaza and 81,026 others have been injured.

"Never before in history has such a large number of mass killing tools been amassed and employed together in front of the world as is happening now in Gaza, where the population is deprived of water, food, medicine, electricity, and fuel, crushing the infrastructure, destroying all institutions, disrupting sanitation, spreading epidemics, crushing the health system, implementing the siege, closing crossings, and preventing the entry of medical supplies and delegations," the Gaza Health Ministry said.

-ABC News' Will Gretsky

An Israeli government official said the Israeli Prime Minister’s Office wasn’t informed that President Joe Biden’s Friday remarks would include a permanent end to the fighting.

“If you listen to what Biden said, you come to the impression that we agree to a permanent cease-fire without, or, without our conditions being met, and that's not the case,” the official said.

The official said the Israeli Prime Minister’s Office, including Prime Minister Benjamin Netanyahu, was informed 30 minutes before that Biden was giving a speech. The official said Netanyahu was told that the speech would focus on the hostages, with no mention of implementing a permanent cease-fire.

A senior U.S. official said the Biden administration "engaged with the Israelis at multiple levels before the president delivered the speech." The official said the U.S. specifically engaged with the Israeli Prime Minister's Office and the Israeli war cabinet.

The official also pointed to when Biden said in his speech that it was a proposal that the Israelis agreed to. The official noted that Netanyahu himself said that it was an Israeli proposal.

An Israeli official and two other Israeli sources who are familiar with the matter told ABC News that what Biden presented is indeed the outline of the Israeli proposal. The sources said the proposal was approved by all war cabinet members, including Netanyahu, and sent to the mediators earlier in the week.

The sources added that there are “interpretation gaps,” referring to the way the outline was presented by Biden.

Biden presented on Friday what he said was an Israeli proposal to draw the war in Gaza to a close.

Biden said the deal had been transmitted to Israel and Hamas, through Qatar.

The president said the first phase would last for six weeks and include a "full and complete cease-fire, a withdrawal of Israeli forces from all populated areas of Gaza [and] release of a number of hostages." Palestinians would also be able to return to their homes and 600 trucks of humanitarian aid would be delivered to Gaza every day.

The second phase would include a release of all remaining living hostages and the temporary cease-fire would become a permanent cease-fire with Israel withdrawing all forces from Gaza "as long as Hamas lives up to its commitments," Biden said.

In phase three, there would be a major reconstruction of Gaza.

-ABC News’ Britt Clennett, Dana Savir and Michelle Stoddart