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 Egyptian border guard was killed in a shooting in the Rafah border area with Gaza, Egypt’s military spokesman said in a statement on Monday.

"The Egyptian armed forces, through the competent authorities, are investigating a shooting incident in the Rafah border area which led to the martyrdom of one of the security personnel on duty," the statement said.

The Israeli military had earlier reported an exchange of fire on the Egyptian border and said it was discussing the incident with Egypt.

“A few hours ago (Monday), a shooting incident occurred on the Egyptian border. The incident is under review and discussions are being held with the Egyptians,” the IDF said.

Initial investigations into an incident that killed an Egyptian border guard indicate the incident occurred while there was an exchange of fire between Israeli forces and "the Palestinian resistance," an Egyptian security source told Egypt’s state-affiliated Al Qahera News TV on Monday.

In October 2023, weeks after the war started, Israel said one of its military tanks mistakenly fired at an Egyptian position near the border with Gaza. Egypt said at the time that several army personnel were slightly injured.

Tensions between Egypt and Israel have escalated after Israeli forces earlier this month seized control of the Rafah border crossing, a key entry point for humanitarian aid. Egypt said it would not reopen its side of the crossing unless it is operated by Palestinians and accused Israel of preventing aid deliveries.

-ABC News' Ayat Al-Tawy