An American doctor who refused an evacuation from southern Gaza on Friday said he stayed behind in solidarity with colleagues who were unable to leave, calling on President Biden to help ensure the safety of medical workers treating patients impacted by the war.

“I have never in my career witnessed the level of atrocities and targeting of my medical colleagues as I have in Gaza,” Adam Hamawy, a former U.S. Army combat surgeon, said in a statement to The Washington Post on Saturday.

“I want our President to know that we are not safe,” he said. “As a doctor, I cannot abandon the remaining members of my team, and as a former soldier, I cannot abandon my fellow Americans.”

Hamawy, 53, a reconstructive plastic surgeon, traveled to the Gaza Strip with the Virginia-based Palestinian American Medical Association, a medical mission coordinated by the World Health Organization. His 19-person team, including U.S. citizens and nationals from other countries, arrived in the territory through the Rafah border crossing on May 1 to support the European Hospital in nearby Khan Younis.

Over seven months of war, Israel has besieged and destroyed Gaza’s most critical medical facilities, detaining doctors and other health-care workers, and forcing staff at at least two hospitals to bury dead patients in mass graves. The remaining hospitals and clinics are barely functioning, the WHO says, and face shortages of medicine, equipment and personnel.

Hamawy and his colleagues, who arrived with suitcases full of supplies, including much-needed anesthetics, were scheduled to leave Gaza on May 13. But soon after they arrived, Israeli forces launched an operation in Rafah to seize the border crossing with Egypt and target Hamas militants holed up in the area.

The border was closed and the doctors were trapped.

As the fighting intensified, they treated the influx of trauma patients, many of them children, and almost immediately started running low on alcohol pads, gauze and burn cream.

“We don’t even have absorbent pads to keep [patients’] wounds dry, which is necessary to prevent hypothermia,” one of the U.S. doctors, Mahmoud Sabha, wrote in an op-ed in the Los Angeles Times on Wednesday.

More than 35,000 people have been killed in Gaza since the war began, according to the local health ministry. The ministry does not distinguish between civilians and combatants but says the majority of those killed are women and children.

Israel launched the war in Gaza after Hamas militants staged a brutal attack on Israeli communities Oct. 7, killing around 1,200 people and kidnapping more than 250. It accuses Hamas and other Palestinian fighters of using hospitals as bases for militant activity.

“We worry that the European Hospital we currently are in will suffer a similar fate of al-Shifa and Nasser hospitals,” Hamawy said, referring to the two largest hospitals in Gaza, which were severely damaged by Israeli military raids.

He is one of three U.S. medical volunteers who stayed behind, while other colleagues evacuated through the Kerem Shalom crossing between Israel and Gaza, with the help of the U.S. Embassy in Jerusalem. Only U.S. citizens were given permission to leave.

Eleven team members from other countries, as well as two U.S. permanent residents, were not offered exit, Hamawy said in a text message early Saturday.

“When the call came to evacuate, I was asked to choose to either evacuate and leave my team behind or stay with them. I could not in good conscience leave my team behind,” he said in the statement.

“That was not what I was taught,” he continued. “That is not the Soldiers Creed. We don’t leave Americans behind. This is against our values as Americans,” he said.

Hamawy, who lives in New Jersey, was among the doctors Sen. Tammy Duckworth (D-Ill.) has publicly credited with saving her life in Iraq in 2004.

The Palestinian American Medical Association has another group of volunteers waiting in Egypt to relieve Hamawy’s team - but the entry of foreign aid workers into Gaza has been severely restricted since Israel closed the Rafah border.

Hamawy and his colleagues don’t know when they might get the opportunity to leave. In his statement, Hamawy apologized to his family for not going home.

“I know it hurts that I am not coming home this weekend, and I am sorry,” he said. “But I know that you are proud that I am upholding my oath to never leave anyone behind.”

In a message to The Post, he said, “if all the U.S. citizens left, what would that say about us as a country? That is not who we are.”