It comes as medics say the Israeli Defence Forces (IDF) killed at least 13 people in northern Gaza and continued to demolish homes in Rafah in the south.
MSF – also known as Doctors Without Borders – called on Israel to “lift the inhumane and deadly siege” and for all parties to restore the ceasefire.
“Gaza has been turned into a mass grave of Palestinians and those coming to their assistance,” said Amande Bazerolle, MSF emergency coordinator.
“We are witnessing in real time the destruction and forced displacement of the entire population in Gaza.”
Sky News have contacted the IDF for a response to the MSF’s claims.
Israel’s invasion of Gaza has killed more than 51,000 people, according to the enclave’s Hamas-run health ministry.
The UN says 409 aid workers have been killed in Gaza since the IDF’s ground offensive began.
Ms Bazerolle added: “With nowhere safe for Palestinians or those trying to help them, the humanitarian response is severely struggling under the weight of insecurity and critical supply shortages, leaving people with few, if any, options for accessing care.”
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Meanwhile, Israel’s defence minister said troops will remain in so-called security zones in Gaza indefinitely.
“Unlike in the past, the (Israeli military) is not evacuating areas that have been cleared and seized.”
The military will remain in these “security zones” in any temporary or permanent situation in Gaza – “as in Lebanon and Syria”, Mr Katz added.
The collapsed ceasefire agreement – which fell apart between phases one and two – had included provisions for a full Israeli withdrawal from Gaza.
Mr Katz also said that Israel would continue to refuse humanitarian aid getting into Gaza – he claimed as a way of pressuring Hamas.
Hamas has said it will not release dozens of remaining hostages without a complete Israeli withdrawal from Gaza and a lasting ceasefire.
The renewed war in Gaza over the last year and a half followed deadly Hamas attacks on Israel which killed 1,200 people, mostly civilians, and saw around 250 taken hostage.
