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

A high-level Egyptian source denied Israeli reports about the existence of tunnels on the Egyptian border with Gaza, Egyptian state-run Al-Qahera News said.

The source dismissed the reports as “lies” promoted by Israel to "cover up its military failure." It added that there were "no communications with the Israeli side" regarding the allegations.

There has been no official comment from Cairo since the announcement.

Egypt has over the past decade destroyed hundreds of smuggling tunnels along its eastern border with Gaza as part of its fight against Islamist militants in its border Sinai region.

Egyptian officials have said a potential Israeli takeover of Philadelphi, a largely demilitarized buffer zone along the Gaza-Egypt border, could violate the 1979 peace deal between Egypt and Israel.

-ABC News' Ayat Al-Tawy