The Israeli Defense Forces (IDF) claimed two top Hamas officials were killed in the deadly airstrike in western Rafah Sunday night.

The IDF said Hamas' Chief of Staff in the Judea and Samaria wing, Yassin Rabia, and an additional senior Hamas official, Khaled Nagar, were both killed.

"Hamas' Judea and Samaria wing is responsible for the planning, funding, and carrying out of terror attacks throughout Judea and Samaria and within Israel," the IDF said in a statement Sunday.

The IDF claimed Rabia was responsible for "numerous murderous terror attacks, including in 2001 and 2002, in which IDF soldiers were killed."

The IDF also claimed Nagar "directed shooting attacks and other terrorist activities in Judea and Samaria, and transferred funds intended for Hamas' terrorist activities in the Gaza Strip."

"Previously, Khaled Nagar carried out several deadly terror attacks between 2001-2003 which led to the deaths of several Israeli civilians and the injury and death of several Israeli soldiers," the IDF claimed.

The airstrike in Rafah on Sunday also resulted in the deaths of at least 50 individuals, including civilians, according to Action Aid UK.

The death toll in the IDF airstrike that hit western Rafah Sunday night has risen to at least 50 individuals, including civilians, according to Action Aid UK.

The organization said Israeli fighter jets launched eight missiles at makeshift shelters housing internally displaced persons next to UNRWA warehouses stocking vital aid.

"We are outraged and heartbroken by the recent attacks in West Rafah," Action Aid UK said in a statement Sunday.

"These shelters were supposed to be safe havens for innocent civilians, yet they became targets of brutal violence," the organization continued. "Children, women, and men are being burned alive under their tents and shelters."

Action Aid UK expects the number of casualties to rise.

-ABC News’ Victoria Beaule

A deadly airstrike has killed at least 35 people inside western Rafah, near the UNRWA logistics base in Tal Al-Sultan, according to officials at the Hamas-run Gaza Ministry of Health.

Numerous individuals remain stuck in a fire that resulted from the airstrike and in the tents destroyed by the bombardment.

The Israeli Defense Forces (IDF) confirmed the airstrike to ABC News in a statement on Sunday and acknowledged that civilians were harmed as a result of the strike.

"A short while ago, an IDF aircraft struck a Hamas compound in Rafah in which significant Hamas terrorists were operating. The strike was carried out against legitimate targets under international law, using through the use of precise munitions and on the basis of precise intelligence that indicated Hamas' use of the area," the IDF said.

"The IDF is aware of reports indicating that as a result of the strike and fire that was ignited several civilians in the area were harmed," the IDF continued, adding, "The incident is under review."

-ABC News' William Gretsky

Palestinian medic sources tell ABC News that at least 25 people are dead following a strike in northwest Rafah on Sunday night, near the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) headquarters there.

The area is densely populated with tents for internally displaced people, the sources said.

In a statement, the Palestine Red Crescent Society claimed "Israeli aircraft have shelled several tents in this area," resulting in injuries and deaths.

"Many have been transported to the Tal Al-Sultan clinic and the field hospitals near the sea in Rafah. Currently, numerous individuals remain trapped under the flames and in the tents destroyed by the bombardment," the organization said in its statement.

ABC News has reached out to the Israel Defense Forces for comment.

-ABC News' Samy Zyara and Anna Burd