Lebanon's parliament will meet on January 9 to elect a new president, seeking to end more than two years without a head of state, official media reported Thursday, a day after an Israel-Hezbollah ceasefire began.

The official National News Agency also reported that parliament on Thursday extended the mandate of army chief Joseph Aoun, himself floated as a potential presidential contender.

"Speaker Nabih Berri called a parliament session to elect a president of the republic on January 9," the NNA reported.

A Syria war monitor on Thursday said clashes between the army and jihadists killed more than 130 combatants in the worst fighting in the country's northwest in years, as the government also reported fierce battles.

The Britain-based Syrian Observatory for Human Rights said jihadist group Hayat Tahrir al-Sham (HTS) and allied factions launched a surprise attack on the Syrian army in the northern province of Aleppo on Wednesday.

The OPEC+ alliance of major oil-producing nations has postponed a weekend meeting to December 5 in what analysts said were signs of disagreement among the group over plans to increase output.

The 22-member OPEC+ group led by Saudi Arabia and Russia was due to decide on its 2025 output policy at a ministerial meeting originally scheduled for Sunday.

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.