Seventy-six injured Gazan residents have crossed from Gaza into Egypt on Wednesday, hours after the Rafah border crossing opened for the first time since the Israel-Hamas conflict began on Oct. 7, according to Palestinian Rafah Crossing spokesman Wael Abu Omar.

The World Health Organization said it's working with officials in Egypt to help establish "a comprehensive triage, stabilization, and medical evacuation system" and "ensure that psychological trauma support services are available to patients."

At least 335 foreign passport holders -- including dual nationals and foreigners -- also crossed from Gaza into Egypt on Wednesday, he said.

As the humanitarian crisis in Gaza worsens, 51 aid trucks crossed the border Wednesday to head into Gaza, he said. A total of 268 aid trucks have now entered Gaza.

President Joe Biden posted on social media on Wednesday confirming that the U.S. "secured safe passage for wounded Palestinians and for foreign nationals to exit Gaza."

"We expect American citizens to exit today, and we expect to see more depart over the coming days," Biden wrote.

Five American aid workers are among the foreign nationals who crossed the Rafah border from Gaza into Egypt on Wednesday, according to the Palestinian Children's Relief Fund.

A Rafah crossing spokesman said at least 335 foreign passport holders -- including dual nationals and foreigners -- have crossed from Gaza into Egypt.

Five American aid workers have crossed the Rafah border from Gaza into Egypt, according to the Palestinian Children's Relief Fund. They work for the Palestinian Children's Relief Fund, Catholic Relief Services and Doctors Without Borders.

The border crossing between Gaza and Egypt opened on Wednesday, allowing some foreign nationals and injured Gaza residents to exit the enclave for the first time since the Israel-Hamas conflict began on Oct. 7.

Seventeen ambulances, each transporting one injured Gazan, have crossed the border into Egypt, ABC News has confirmed.

The Rafah border crossing, which is controlled by Egypt, was expected to allow about 500 foreign passport holders to exit, according to the Gaza Borders and Crossings Authority, which released a list of names of those who would be allowed across.

At least 110 dual nationals have crossed the Rafah border into Egypt, ABC News confirmed.

Five American aid workers are among those at Rafah waiting to cross into Egypt, according to the Palestinian Children’s Relief Fund.

Doctors Without Borders called for a ceasefire Saturday saying the conflict has reached "a new low in an endless stream of unconscionable violence." The organization, which has been providing medical care to people in Gaza, also condemned world leaders for not calling for a ceasefire.

"The deadly attack outside the gate of Al-Shifa hospital impacting an ambulance is horrendous. This is a lethal attack outside Gaza's main and busiest hospital, where our staff work daily to provide lifesaving medical care. We have repeatedly called for an immediate and total ceasefire, for the protection of healthcare facilities, as well as medics, patients and people who are taking shelter there," Doctors Without Borders said in a statement Saturday.

"This is a new low in an endless stream of unconscionable violence. The repeated strikes on hospitals, ambulances, densely populated areas and refugee camps are disgraceful. How many people have to die before world leaders wake up and call for a ceasefire?" Doctors Without Borders said.

This comes as the Palestinian death toll rises to 9,488 -- including 3,900 children and 3,509 women -- and 24,158 Palestinians were injured, according to the Hamas-run Gaza Health Ministry.

One physician described seeing an ambulance hit outside Al-Shifa hospital.

"We were standing inside the hospital gate when the ambulance was directly hit in front of us. There were bloody bodies everywhere. Many were killed immediately, while we rushed others to the operating room for emergency care," Dr. Obaid, a Doctors Without Borders doctor at Al Shifa hospital, said.

The Israel Defense Forces claimed its aircraft hit an ambulance that it believes was being used by Hamas and called for civilians to move south for safety.

-ABC News' Cindy Smith and Emma Ogao