UN refugee chief Filippo Grandi said an Israeli air strike hit "humanitarian structures" Saturday at a border crossing between Lebanon and Syria that was previously hit last month.

The crossing, known as Jousieh on the Syrian side, became a key escape route for those fleeing the Israel-Hezbollah war after the main border crossing between the two countries was hit.

But it was put out of service late last month when an Israeli strike created a large crater that blocked vehicle traffic.

A Lebanese military source said Saturday that unidentified naval commandos abducted a trainee mariner in the coastal city of Batroun, in an operation a judicial official said was likely carried out by Israel.

"A naval commando force kidnapped a civilian," the military source said on condition of anonymity, adding an investigation was underway to determine whether the operation was carried out by Israel.

A Lebanese judicial official said Israel was likely behind the "kidnapping operation", the first of its kind since the Israel-Hezbollah war erupted in September.

Iran's supreme leader vowed retaliation on Saturday for attacks by Israel, as an Israeli military official confirmed naval commandos seized a suspected Hezbollah operative in a raid in Lebanon.

The World Health Organization said four children were among six people wounded in a strike on a polio vaccination centre in north Gaza, where UN agencies have spoken of "apocalyptic" conditions in the face of a blistering Israeli assault.

Less than a week before the United States presidential election, Americans living in settlements in the Israeli-occupied West Bank know exactly who they want to win: Donald Trump.

Recent polls show that a majority of Israelis, 66 percent according to one conducted by Israel's Channel 12 News, dream of the days when the former president inhabited the White House.

As Palestinian-American entrepreneur Jamal Zaglul stood by his olive press at the end of harvest season in the occupied West Bank, his mind was far away on next week's US election.

Like other US passport holders living in Turmus Aya -- where they form the majority -- he was sceptical the ballot would bring change to the region.

"Here we have problems. Nobody (in the US) cares about us," said the businessman in his 50s.

The UN peacekeeping chief said Friday that the blue helmet force in Lebanon will hold its line despite facing attacks in recent weeks, adding that its positions would be "occupied" if it left.

More than 10,000 peacekeepers with the UNIFIL mission have been stationed in southern Lebanon since 1978 and are tasked with monitoring the "Blue Line" of demarcation with Israel.

Coco Gauff believes bringing the WTA Finals to Saudi Arabia can "open doors" and inspire positive change for women in the country, although the world number three admitted: "I'd be lying to you if I said I had no reservations".

The WTA has signed a three-year deal with the Saudi Tennis Federation to stage its season finale in Riyadh, with the first edition kicking off at King Saud University Indoor Arena on Saturday.

Minutes from the heart of Beirut, the Lebanese capital's once vibrant southern suburbs lie largely deserted save for black-clad Hezbollah militants standing guard amid the rubble.

Huge portraits of the movement's slain leader Hassan Nasrallah and other commanders killed in the blistering air campaign Israel launched in late September flutter in the wind alongside the movement's yellow flag -- in some cases painted red to signal vengeance.

The smell of gunpowder still pervades the area after Israel pounded it with at least 10 air strikes before dawn on Friday.

While heeding US calls to steer clear of nuclear or oil infrastructure, Israel in its strikes on Iran inflicted severe damage on Iranian air defences and missile capacities and could yet launch more widescale action against the Islamic republic, analysts say.

Following Iran's October 1 salvo of missiles against Israel last month -- intended as a reprisal to Israeli strikes that killed senior figures in Iran-backed groups Hezbollah and Hamas -- there were fears Israel would respond with attacks on Iran of a magnitude that could spark a global conflict.

The news came by video. Law professor Ali Mourad discovered that Israel had dynamited his family's south Lebanon home only after footage of the operation was sent to his phone.

"A friend from the village sent me the video, telling me to make sure my dad doesn't see it," Mourad, 43, told AFP.

"But when he got the news, he stayed strong."

The aerial footage shows simultaneous explosions rock a cluster of buildings on a lush hill.

Mourad's home in Aitroun village, less than a kilometre from the border, is seen crumpling in a cloud of grey dust.