Joe Biden and Benjamin Netanyahu speak for the first time in weeks — has their relationship soured as the Middle East war escalates?

US President Joe Biden and Israeli Prime Minister Benjamin Netanyahu have broken nearly two months of silence with a phone call at a tense time in the Middle East — and in their relationship.

It is thought to be the pair's first known chat since August 21 and it happened just a day after leaked extracts from a new book exposed rising, sometimes expletive-laden tension between the leaders.

Netanyahu scheduled the call after telling his Defence Minister Yoav Gallant to cancel a planned trip to Washington until after he had spoken to Biden.

The country is in the middle of planning its retaliation to Iran's 180-strong missile bombardment of Israel last week — with fears the ongoing tit-for-tat could lead to a broader regional war.

Biden and Netanyahu — who were joined by Vice-President and Democratic presidential candidate Kamala Harris — spoke for 30 minutes. The relationship between the sworn allies is showing signs of strain, as Israel's hostilities with Gaza, Lebanon and Iran have grown in recent weeks.

Here's what we know about the call and the tension in the US-Israel relationship.

Is the US putting more pressure on Israel?

Israel's UN Envoy says the call was positive and "we appreciate the support of the US".

White House spokesperson Karine Jean-Pierre says the call was "direct" and "productive" and included discussions on a potential attack on Iran.

But in recent months, the US is getting more frustrated with the way Netanyahu is waging the escalating war.

The US State Department on Wednesday, local time, warned that it would be unacceptable for Israel's military incursion in southern Lebanon to evolve into a situation similar to its invasion of the Gaza Strip.

Ori Goldberg, a Middle Eastern expert and former advisor on Middle Eastern Affairs for the Israeli government, tells the ABC he gets the sense that the Americans are exerting real pressure on Israel, perhaps for the first time this year.

"American presidents during the last months of their time in office have often done things that they did not dare to do while being in office," he says.

"It remains to be seen whether Biden will find the gumption necessary to challenge Netanyahu. He might, then again, he might not, because he doesn't want to."

What did Biden say about Netanyahu in private?

The call could likely be a little more tense than usual, given remarkable extracts released from legendary Washington Post journalist Bob Woodward's new book, War.

Woodward recounts an increasingly frayed relationship between the men, with Biden reportedly calling Netanyahu a liar amid other outbursts.

"Bibi, what the f***?," the president reportedly yelled at Netanyahu in July, after the assassination of Hamas leader Ismail Haniyeh in Iran and strikes near Beirut. "You know the perception of Israel around the world increasingly is that you're a rogue state, a rogue actor."

Goldberg says there is no love lost between the two men.

"Biden is a true Zionist, an ardent supporter of Israel and Netanyahu, who thinks he has a better chance of getting his way under the Trump administration, has tried to play Biden for a fool, has humiliated Biden repeatedly," Goldberg says.

"I have no doubt Biden has no liking for Netanyahu."

Why did Netanyahu block his defence minister?

Yoav Gallant was supposed to fly to Washington on Wednesday to visit the Pentagon and the US Secretary of Defence Lloyd J. Austin to discuss Israel's retaliation on Iran.

But the day before he was due to leave, he said he postponed it at Netanyahu's request.

There has long been a rivalry between Netanyahu and Gallant, with the two frequently being at odds over how the war in Gaza should be fought.

The cancellation tells us something about the tension in Netanyahu's team, but it also throws doubt on the timeline for Israel's promised retaliation against Iran.

Goldberg says the postponed visit is a sign that it's further delayed.

"The more delayed it is, the less I think there's a chance of it materialising as fully as Israel has claimed. I think if we see anything, it'll be a profoundly dilapidated response. And I think that's also classic Netanyahu. Netanyahu likes to play both ends against the middle."

But Gallant doubled down in a video issued by his office on Wednesday night: "Whoever attacks us will be hurt and will pay a price. Our attack will be deadly, precise and above all surprising, they will not understand what happened and how it happened, they will see the results."

Rumours of potential targets for Israel's strike include the oil industry and nuclear weapon facilities, but it's considered that military targets are more likely.

Iran is also talking to allies for support

Meanwhile, Iran's Foreign Minister Abbas Araqchi is also shoring up support abroad, arriving in Saudi Arabia on Wednesday morning, before visiting Qatar later in the day.

Araqchi met with Saudi officials as part of his visit.

"Our relations with Saudi Arabia are growing and are progressing in a good direction," he said. "The purpose of my trip is, of course, to consult on regional issues and changes that are taking place in the region: In Lebanon, in Gaza and the crimes that the Zionist regime is committing, the refugees who are now in Lebanon and how to help them, the discussion of regional issues is the main purpose of my trip to the region."

Iran has also told Gulf Arab states it would be "unacceptable" if they allowed the use of their airspace or military bases against Iran and warned that any such move would draw a response, a senior Iranian official told Reuters.

Bahrain, Kuwait, Qatar, Saudi Arabia and the United Arab Emirates all host US military facilities or troops.

What about fighting in Lebanon, Gaza and Israel?

Fierce fighting rages on both sides of the Lebanon-Israel border, plus the IDF's raid into northern Gaza continued for a fifth day.

Lebanon's Hezbollah said its fighters had pushed back advancing Israeli forces in border clashes, including in a village where Israeli troops had been filmed hoisting an Israeli flag.

But Israel continued air strikes into Lebanon, particularly across the country's south. Beirut's iconic waterfront, streets and schools are overflowing with people who have moved north, seeking shelter.

On Tuesday, 22 people were killed and 80 were wounded, the Lebanese health ministry says, with more than 2,100 killed since October last year.

The UN Office of the High Commissioner for Human Rights says a quarter of Lebanon is now under Israeli military displacement orders.

South of the border, rocket sirens sounded constantly across northern Israel on Wednesday, with two people killed in strikes on Kiryat Shmona near the border and at least six wounded in the major port city of Haifa, according to Israeli authorities.

While eyes are on Lebanon, Israel has also intensified its action in Gaza in recent days.

The raid — which the IDF says is intended to stop Hamas fighters staging further attacks and regrouping — has been focused on the region's north for the last week, particularly around the city of Jabalia. At least 60 people were killed in Israeli military strikes on Wednesday, Palestinian medics said.

Israel has repeatedly issued evacuation orders in the area, but Palestinian and UN officials say there are no safe places to flee to.

The United Nations World Food Program on Wednesday said that aid entering the Gaza Strip has plummeted to its lowest level in months, forcing the agency to stop the distribution of food parcels this month.