The White House said Wednesday it wanted "answers" from Israeli authorities after the discovery of mass graves at two Gaza hospitals destroyed during Israeli sieges.

Gaza's Civil Defense agency said health workers uncovered at least 392 decomposing bodies of people killed and buried by Israeli occupation forces at the Nasser Medical Complex in Khan Younis following their withdrawal from the medical facility.

Around 30 bodies were found buried in two graves in the Al-Shifa Hospital courtyard in Gaza City.

"We want answers," National Security Advisor Jake Sullivan told reporters. "We want to see this thoroughly and transparently investigated."

Reporter: Evidence at Gaza mass graves show torture and signs of being buried alive, Palestinians called for an independent investigation, what’s wrong with that?

Patel: We’re asking Israel

Reporter: You’re asking the accused to investigate itself?

Patel: We’re asking Israel pic.twitter.com/fIWO3MHPwv

— Assal Rad (@AssalRad) April 25, 2024

The European Union also backed a United Nations demand for an independent probe into the graves.

"This is something that forces us to call for an independent investigation of all the suspicions and all the circumstances, because indeed it creates the impression that there might have been violations of international human rights committed," EU Spokesperson Peter Stano indicated.

"That's why it's important to have independent investigation and to ensure accountability."

UN rights office 'horrified' by the destruction

The UN rights office said Tuesday that international investigators should be involved in a probe into the discovery of the bodies.

The UN rights office said it was "horrified" by the destruction of Gaza's two biggest hospitals, Al-Shifa in Gaza City and the Nasser Medical Complex in Khan Younis.

The office demanded "independent, effective, and transparent investigations into the deaths."

"Given the prevailing climate of impunity, this should include international investigators," UN rights chief Volker Turk said in a statement.

"Hospitals are entitled to very special protection under international humanitarian law," Turk stressed, pointing out that "the intentional killing of civilians, detainees and others who are hors de combat is a war crime."

The UN rights office said it did not have access to independent information as to what happened at the two hospitals. But spokeswoman Ravina Shamdasani said efforts were underway to verify reports and details given by the authorities in Gaza.

"Victims had reportedly been buried deep in the ground and covered with waste," she told reporters in Geneva, adding that older people, women, and wounded were reportedly among the dead.

Others were allegedly "found with their hands tied and stripped of their clothes."

Palestinian Civil Defense member Mohammad al-Moghier expressed his team's preparedness to complete an evidential report for an independent investigation into the mass graves discovered at the Nasser Hospital.

France and Germany

In the same context, France called for an independent probe into the case, describing the discovery of the mass graves near al-Shifa and Nasser hospitals as "extremely troubling".

The French Foreign Ministry underlined that the situation of civilians in Gaza "has been unacceptable for far too long," and renewed its calls "for an immediate and lasting ceasefire, the only thing that will protect civilian populations, and a massive influx of humanitarian aid through all Gaza Strip access points."

Germany also echoed France's calls for an investigation and said it is aware of the "shocking" media reports about the discovery of the mass graves.

Read more: South Africa calls for investigation into Gaza hospitals mass graves