Former U.S. presidential candidate and former U.N. Ambassador Nikki Haley visited the northern Israeli border on Tuesday, meeting with Israeli soldiers and Israelis.

During her visit, Haley visited an Israel Defense Forces post with soldiers serving on the northern border.

Haley stopped and signed artillery shells, writing, "Finish them! America loves Israel!" on some of them.

-ABC News' Ellie Kaufman

One million Palestinians have been forced to flee Rafah over the last three weeks in search of safety, according to the United Nations Relief and Works Agency for Palestine Refugees in the Near East.

Heavy bombardment continued in Gaza overnight, including in Tal Al Sultan, where the U.N. main offices in Gaza are located, according to UNRWA Commissioner-General Philippe Lazzarini.

Most of the UNRWA staff could not make it to work as they are packing up and moving. The UNRWA is also running out of medical supplies and basic human medicines, according to Lazzarini.

Just over 200 trucks with humanitarian supplies were picked up in southern Gaza in the last three weeks as needs continue to increase exponentially, Lazzarini said.

-ABC News' Will Gretsky

The United Nations secretary-general has condemned the deadly strike on Rafah "in the strongest terms," saying Antonio Guterres is "heartbroken by the images of the killed and injured," his spokesman, Stephane Dujarric, said in a statement Tuesday.

"The Secretary-General reiterates his demand for an immediate ceasefire and the immediate and unconditional release of all hostages. He recalls the recent orders of the International Court of Justice, which are binding and must be complied with," Dujarric said.

"The humanitarian catastrophe in Gaza is now compounded by the unconscionable prospect of a man-made famine," Dujarric said.

-ABC News' Ellie Kaufman

Israel Defense Forces spokesperson Lt. Col. Nadav Shoshani admitted to a "mishap" in Sunday's Rafah strike that killed 50 Palestinians and injured at least 249 others, saying it was a "tragic incident that shouldn't have happened."

"The outcome is not the outcome we had in mind when this operation started. That's why we're investigating it. It's a tragic event and it's not the way we operate. We are fighting with Hamas terrorists. We are trying to kill them specifically in a very precise way, intelligence based. And that's why we look at this as a tragic incident that shouldn't have happened," Shoshani said.

Over 36,000 Palestinians have been killed in Gaza since Oct. 7.

Israeli Prime Minister Benjamin Netanyahu called the strike a "tragic mishap" on Monday.

"The mishap was the fire that carried out after the targeted attack, and we are looking into why this fire caught on," Shoshani said. "The attack, per se, was according to procedure, with surveillance before the attack, a very precise attack based on intelligence."

-ABC News' Britt Clennett

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