The US on Saturday deployed a second aircraft carrier "to deter hostile actions against Israel" while President Joe Biden pushed for the protection of civilians amid the American ally's siege and bombardment of Gaza.

The presence of the USS Eisenhower and its affiliated warships in the eastern Mediterranean signals Washington's "ironclad commitment to Israel's security and our resolve to deter any state or non-state actor seeking to escalate this war," Secretary of Defense Lloyd Austin said in a statement.

Several thousand people demonstrated in a pro-Palestinian rally in Geneva on Saturday as Israel readied troops for an expected invasion of the Gaza Strip.

Police and organisers said around 6,000 people attended, national broadcaster RTS reported. The Tribune de Geneve newspaper gave the same figure.

Protesters marched behind a banner reading "Free Palestine" and chanted "Long live Palestine" and "Israel: assassins", while dozens waved Palestinian flags.

Demonstrators marched under heavy police escort.

Thousands of Palestinians have gathered in the south of the Gaza Strip, laying out beds on the streets after UN-run schools filled up following Israel's warning to evacuate the north of the impoverished enclave.

Israel on Friday called on the 1.1 million inhabitants of northern Gaza to evacuate, ahead of an expected ground offensive following last week's surprise Hamas attack on Israeli territory.

In Nasser Hospital in Khan Yunis, thousands of uprooted people gathered in the yard and in hallways, searching for food, water and a place to sleep, according to AFP journalists.

Volunteers toiled away at Tel Aviv's convention centre, doing "anything our government fails to", said an Israeli protest leader who has helped turn his movement into a huge relief operation since last weekend's Hamas attack.

For 39 straight weeks, opponents of the hard-right government's divisive judicial overhaul had brought tens of thousands of people onto the streets in what became the biggest protest movement in Israel's history.

Hamas militants seized about 120 hostages when they unleashed a surprise attack on Israel and gunned down more than 1,300 people, including civilians, on October 7, the Israeli army said.

Here is what we know about the hostages and the efforts being made to free them.

- Is there proof of life? -

After a week of uncertainty, the Israeli army said Hamas had taken at least 120 people captive, including civilians and soldiers, and estimates their total number could be 150, without being certain if they are alive or dead.

France on Saturday urged the Iranian-backed Hezbollah militia to stay out of the conflict between Israel and Hamas, expressing concern at the situation on the Lebanon-Israel border.

Paris also called for reporters covering the Israel-Hamas war to be protected after one journalist was killed and six others wounded in firing along the Lebanese border on Friday.

Hezbollah and Lebanon must "exercise restraint to avoid opening a second front in the region", of which "the first victim will be Lebanon", the French presidency said in a statement Saturday.

International aid groups and major powers have pleaded with Israel to set up safe zones in Gaza where thousands struggled Saturday to get out of the north of the Palestinian territory, under threat of attack.

With thousands of Israeli troops massed around Gaza's borders, uncertainty over when Israel could launch a ground operation in reprisal for deadly raids by Hamas has added to the turmoil in Gaza.

"We fear an unprecedented humanitarian catastrophe," said Ivan Karakashian of the Norwegian Refugee Council.

Two Lebanese civilians were killed in Israeli shelling of the southern village of Shebaa on Saturday, its mayor told AFP, the latest casualties of cross-border tensions over Israel's war with Hamas.

Iran-backed militant group Hezbollah and Palestinian factions in Lebanon have exchanged cross-border fire with the Israeli army since a shock October 7 attack by Hamas killed more than 1,300 people in Israel.

US Secretary of State Antony Blinken called Saturday on China, a partner of Iran, to use its influence to push for calm in the Middle East.

The top US diplomat, who was visiting Saudi Arabia, had a "productive" one-hour telephone call with Chinese Foreign Minister Wang Yi, State Department spokesman Matthew Miller said.

"Our message was that he thinks it's in our shared interest to stop the conflict from spreading." Miller told reporters on Blinken's plane from Riyadh to Abu Dhabi.

"He thought it could be useful if China could use its influence."

Lebanon said on Saturday that Israel was behind cross-border fire that killed a Reuters journalist and wounded six others near the border.

Israel's military said it was looking into the circumstances of the fatal strike Friday, which also injured journalists from AFP, Reuters and Al Jazeera.

"We are very sorry for the journalist's death," military spokesman Richard Hecht told a briefing, in reference to the Reuters video journalist killed, Issam Abdallah.

On the question of who launched the strike, Hecht said: "We are looking into it."