Prime Minister Benjamin Netanyahu said Thursday that Israel would do "everything" to stop Iran acquiring a nuclear weapon after Iran's top diplomat warned it could end its ban on developing one if Western sanctions are reimposed.

The renewed war of words between the Middle East foes came as Iran prepares to hold key nuclear talks with European governments on Friday which have been overshadowed by their joining with Washington to have Tehran censured by the UN atomic watchdog.

As soon as a truce was announced between Israel and Hezbollah, widow Umm Mohammed Bzeih rushed back to south Lebanon to check on her beloved home, only to find it badly damaged.

"I'm cleaning the rooms so we can stay... though the windows are broken," said Bzeih, 44, the contents of her home strewn everywhere, the curtains ripped and food rotting in the kitchen.

Saudi Arabia announced Wednesday it is ready to open the first part of the Riyadh Metro, a major project intended to help shift the car-centric kingdom to public transport.

Three lines will open to the public on December 1, "with gradual launches completing the six-line, 176-kilometre (109 mile) network across the city," the Royal Commission for Riyadh City said in a statement.

All six lines are expected to be operating by January 5, the statement said.

Surrounded by open shops and busy traffic, residents of northern Israel cautiously welcomed the seeming calm brought by a ceasefire with Hezbollah -- but scepticism was high over whether it would really last.

In a central square in the coastal city of Nahariya, just 10 kilometres (six miles) from the border with Lebanon, old friends Nissim and Meir voiced disappointment with the ceasefire, while others nearby said they still felt unsafe.

Hezbollah lawmaker Hassan Fadlallah said Wednesday the group was cooperating with the army's deployment across south Lebanon under the terms of a ceasefire with Israel, insisting "there will be no problem".

His remarks from the border town of Bint Jbeil came as tens of thousands of residents streamed home after a ceasefire between Israel and Hezbollah took effect before dawn, ending more than a year of hostilities and two months of full-scale war.

They also came as the Lebanese army said it had begun reinforcing its presence in the south.

The mother of a British-Egyptian activist blogger imprisoned in Egypt told UK Foreign Secretary David Lammy on Wednesday she will keep up a two-month-old hunger strike until he is released.

Laila Soueif, 68, who has not eaten for 59 days, met Britain's new top diplomat for the first time to press her case for the UK government to do more to secure the release of her son, Alaa Abdel Fattah.

US President Joe Biden will launch a renewed drive Wednesday for a Gaza ceasefire and hostage release deal after Israel and Hezbollah began a truce in Lebanon, his national security adviser said.

Jake Sullivan said Hamas faces increased pressure to cut a deal now that Lebanon's Iran-backed Hezbollah movement is no longer fighting in solidarity with the Palestinian militant group.

Provisions for immunity from prosecution at the International Criminal Court apply to Israeli Prime Minister Benjamin Netanyahu, the French foreign ministry said Wednesday.

It said the Israeli leader was covered by immunity rules that apply to states which are not a party to the ICC. Israel is not an ICC member.

"A state cannot be held to act in a way that is incompatible with its obligations in terms of international law with regards to immunities granted to states which are not party to the ICC," the French statement said.

People displaced by weeks of bombing on Hezbollah's main stronghold in Beirut returned Wednesday to their devastated neighbourhood, with some calling the ceasefire a "victory" for the militant movement.

The once-densely populated southern suburbs of the Lebanese capital were largely emptied as daily bombardments targeted the area during the Israel-Hezbollah war.

As a ceasefire took hold, thousands of people flocked back to the neighbourhood, with some waving Hezbollah's yellow and green flag.

The search operation for seven people still missing from a dive boat that capsized and sank off Egypt's east coast entered a third day on Wednesday, the governor of the Red Sea province said.

The country released video footage Wednesday morning of the latest tourists rescued from the vessel aboard which at least four people, including one Slovak tourist, died.

The governor's office said the search operation was continuing for seven people still missing after the "Sea Story" was struck by a wave and capsized in the middle of the night on Monday.