GENEVA: The United Nations called Tuesday for an international investigation into reports of mass graves at two Gaza hospitals destroyed in Israeli sieges, saying war crimes might have been committed.

The UN rights office said it was “horrified” by the destruction of Gaza’s biggest hospital, Al-Shifa in Gaza City, and its second largest, the Nasser Medical Complex in Khan Yunis.

Gaza’s Civil Defence agency said Tuesday that health workers had uncovered nearly 340 bodies, updating an earlier figure, of Palestinians allegedly killed and buried by Israeli forces at the Nasser complex.

Israel’s army dismissed claims that its troops had buried bodies during its operation at Nasser as “baseless and unfounded”.

The UN rights 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.