Intense talks are on to free hostages held by Hamas after its attack on Israel, French President Emmanuel Macron said Tuesday, after the mother of a French-Israeli captive begged world leaders to intervene.

"I want to be very cautious here... so as not to endanger the intense talks we are currently conducting," Macron told reporters in the Albanian capital Tirana. "But they are progressing and we are following these talks hour by hour."

Iran's supreme leader Ayatollah Ali Khamenei warned Tuesday that "no one can stop" forces opposed to Israel if it keeps up its bombardment of Gaza in response to the surprise attack by Hamas.

The Islamic republic has maintained close contacts with its allies across the region since Hamas militants stormed across the Gaza border with Israel and killed more than 1,400 people, most of them civilians.

French President Emmanuel Macron on Tuesday condemned Hamas for airing a video of a Franco-Israeli woman the Islamist militant group has taken hostage and demanded her unconditional release.

"It is an ignominy to take innocent people hostage and put them on show in this odious way," the Elysee presidential palace quoted Macron as saying.

President Joe Biden will travel to Israel and on to Jordan Wednesday to meet with both Israeli and Arab leadership, as concerns increase that the raging Israel-Hamas war could expand into a larger regional conflict.

U.S. Secretary of State Antony Blinken announced Biden's travel to Israel as the humanitarian situation in the Gaza Strip grows more dire and as Israel prepares for a possible ground attack on the 141-square-mile (365-square-kilometer) territory to root out Hamas militants responsible for what U.S. and Israeli officials say was the most lethal assault against Jews since the Holocaust.

The U.S. worked to break a deadlock over delivering aid to millions of increasingly desperate civilians in the Gaza Strip, which has been besieged and under assault by Israel since a brutal attack by Hamas militants, as U.S. President Joe Biden prepared to head to the region.

Israeli airstrikes continued to pound Gaza early Tuesday, killing dozens of people in the besieged enclave's south, where Israel told civilians from the north to seek shelter ahead of an expected ground offensive.

Palestinians described intense bombardments early Tuesday near two towns in southern Gaza, where Israel had ordered civilians to seek refuge.

Thousands of people trying to escape Gaza are gathered in Rafah, which has the territory's only border crossing to Egypt. Mediators are pressing for an agreement to let aid in and refugees with foreign passports out. The U.S. hoped to break a deadlock with President Joe Biden set to head to Israel and Jordan on Wednesday.

A battle that killed dozens of civilians and more than a dozen Israeli soldiers nearly a decade ago offers a glimpse of the type of fighting that could lie ahead if Israeli forces roll into Gaza as expected to punish Hamas for its rampage across southern Israel last week.

It was July 19, 2014, during Israel's third war against Hamas. The target was Shijaiyah, a densely populated neighborhood of Gaza City that the army said Hamas had transformed into a "terrorist fortress," filled with tunnels, rocket launchers and booby traps.

Palestinians in besieged Gaza crowded into hospitals and schools on Monday, seeking shelter and running low on food and water. More than a million people have fled their homes ahead of an expected Israeli ground invasion aimed at destroying Hamas after its fighters rampaged through southern Israel.

As the enclave's food, water and medicine supplies dwindled, all eyes were on the Rafah crossing between Gaza and Egypt, where trucks carrying badly needed aid have been waiting for days as mediators press for a cease-fire that would allow them to enter Gaza and allow foreigners to leave. Rafah, Gaza's only connection to Egypt, was shut down nearly a week ago because of Israeli airstrikes.

President Joe Biden is considering a trip to Israel in the coming days but no travel has been finalized, a senior administration official said. It would be a powerful symbol of sympathy and support following the brutal attack by Hamas.

A trip would be a chance for Biden to personally affirm to the Israeli people the U.S. is standing firm behind them. But it would come amid growing fears that a looming Israeli move into Gaza could spark a wider war with devastating humanitarian consequences.

Leaders in Qatar and Kuwait received invitations Monday for a summit in Cairo to be held on Saturday to "discuss developments and the future of the Palestinian cause and the peace process".

State media in both countries announced the invitations a day after Cairo announced its intention to host "a regional and international summit on the future of the Palestinian cause", during a visit by U.S. Secretary of State Antony Blinken.