Palestinians mourn their relatives killed in the Israeli bombardment of the Gaza Strip in Deir al Balah on Wednesday. AP

Israel has ordered more evacuations in southern Gaza's main city as diplomats pressed on with efforts to secure a pause in the war that Hamas says has claimed 20,000 lives.

The United Nations said Israel had issued evacuation orders on Wednesday for large areas of Khan Yunis, where more than 140,000 displaced people were sheltering.

Israel told civilians to leave the north of the besieged Palestinian territory at the beginning of the conflict, urging them to seek safety in southern areas.

But as places for people to go continued to shrink, international outrage has mounted over the rising death toll.

The Hamas government's media office in the Gaza Strip said on Wednesday at least 20,000 people had been killed in the Palestinian territory since the war with Israel began.

It said 8,000 children and 6,200 women were among the dead.

UN relief chief Martin Griffiths deemed it a "tragic and shameful milestone".

Paramedics carry a child injured during Israeli bombardment at a hospital in Rafah, southern Gaza Strip. AFP

In the southern city of Rafah, where fireballs and smoke rose after explosions on Wednesday, residents expressed hope that truce talks would succeed.

"I wish for a complete ceasefire, and to put an end to the series of death and suffering. It's been more than 75 days," said Kassem Shurrab, 25.

Truce talks

Hopes that Israel and Hamas could be inching towards another truce and hostage release deal have risen this week as the head of the Palestinian group visited Egypt and talks were held in Europe.

Qatar-based Hamas chief Ismail Haniyeh arrived in Egypt on Wednesday for talks with the country's intelligence chief Abbas Kamel.

Haniyeh also met Iranian Foreign Minister Hossein Amir-Abdollahian but no details were released.

A child injured during Israeli bombardment receives treatment at the Kuwait Hospital in Rafah on Wednesday. AFP

A Hamas official told the media that "a total ceasefire and a retreat of the Israeli occupation army from the Gaza Strip are a precondition for any serious negotiation" on a hostage-prisoner swap.

Israeli Prime Minister Benjamin Netanyahu said there could be no ceasefire in Gaza before the "elimination" of Hamas.

And US President Joe Biden said of a fresh hostage release deal: "There's no expectation at this point. But we are pushing it."

Mossad director David Barnea held a "positive meeting" in Warsaw this week with CIA chief Bill Burns and Qatari Prime Minister Sheikh Mohammed Bin Abdulrahman Al Thani, a source familiar with the talks told the media.

Qatar, backed by Egypt and the United States, last month helped broker a first week-long truce that saw 80 Israeli hostages freed in exchange for 240 Palestinian prisoners.

Agence France-Presse