Hamas said it would hand over a hostage body on Wednesday, after Israeli forensic services concluded that remains returned a day earlier were not from one of two final deceased hostages.

There was something "fundamentally wrong" with how Israel conducted its military operation in the Gaza Strip and there are "strong reasons to believe" that war crimes have been committed, United Nations Secretary-General Antonio Guterres told Reuters on Wednesday.

Ammar Wadi knew he was risking his life when he set out to get a bag of flour for his family from an aid truck near the Zikim crossing into Gaza in June.

The bodies of two deceased hostages are still thought to be in Gaza. Israeli authorities have been releasing Palestinian prisoners and the bodies of deceased Palestinians detainees in exchange for the return of hostage remains.

Democratic politicians are struggling to strike a balance between U.S. support for Israel and voter outrage over civilian suffering in Gaza.

Palestinian militant group Hamas on Tuesday handed over the remains of one of the last two deceased hostages still in Gaza, the International Committee of the Red Cross said, under terms of the October ceasefire deal.

Israeli forensic services concluded that remains handed over by Hamas on Tuesday were not those of the last two hostages in Gaza, the office of Israel's prime minister said.

Israeli Prime Minister Benjamin Netanyahu and his coalition on Wednesday boycotted a Knesset vote endorsing US President Donald Trump’s plan for Gaza.