Israel and Lebanese Hezbollah “can choose a different path”, Joe Biden’s defence secretary has said, as he urged parties embroiled in Middle East conflict to reach a “viable” diplomatic solution.

Speaking in London alongside UK Defence Secretary John Healey and Australian deputy prime minister Richard Marles, Lloyd Austin vowed his government in Washington would “help Israel”.

But he warned all-out war along the eastern Mediterranean coast could devastate both Israel and the Hezbollah political party, which is a proscribed terrorist organisation in the UK.

Mr Healey hosted the three politicians as part of Aukus deal talks, a security partnership between Australia, the UK and US.

The Defence Secretary described a “cloud of growing global insecurity” over their meeting when he spoke in the Painted Hall at Greenwich’s Old Naval College.

Mr Austin said: “The situation in Lebanon and northern Israel is deeply troubling. Lebanese Hezbollah, an Iranian-backed terrorist group, began firing rockets into Israel unprovoked on the day after the October 7 terrorist assault by Hamas.

“And Hezbollah has not stopped since.

“Like any other state, Israel has a right to defend itself. Almost a year later, tens of thousands of Israelis and Lebanese civilians still cannot safely return home.

“And we now face the risk of an all-out war. Another full-scale war would be devastating for both Israel and Lebanon, so let me be clear: Israel and Lebanon can choose a different path.

“Despite the sharp escalation in recent days, a diplomatic solution is still viable. A diplomatic solution, not a military solution, is the only way to ensure that displaced civilians on both sides of the border can finally go back home.

“So I echo the call of President Biden, President Macron and other leaders yesterday for an immediate 21-day ceasefire. That will provide time for the diplomacy needed to achieve a durable arrangement that will allow Israel and Lebanese civilians to return safely to their homes.

“This time can also be used to conclude and implement a deal to secure a ceasefire in Gaza to bring all of the hostages home. All parties should seize this opportunity.

“It can bring much-needed calm to Israelis, Lebanese and Palestinians whose lives have been turned upside down since the Hamas assault on October 7.”

Asked about whether Israeli prime minister Benjamin Netanyahu is “ignoring” calls for a ceasefire, Mr Austin replied: “Israel has stated that its goal is to return its citizens to their homes in the north and I believe the best and the quickest way to do that is through diplomacy.

“And I think that, I mean there’s no question, that both Israel and Lebanese Hezbollah have stated that they do not want to see an all-out war.

“A war between Lebanese Hezbollah and Israel could be devastating for both entities.”

Earlier on Thursday, Mr Netanyahu had vowed to “strike Hezbollah with full force, and we will not stop until we reach all our goals, chief among them the return of the residents of the north securely to their homes”.

On whether the US has any red lines in the conflict, for example, a ground invasion, Mr Austin said: “We’ve been committed from the very beginning to help Israel and provide the things that are necessary for them to be able to protect their sovereign territory, and that hasn’t changed and won’t change.”

The talks in Greenwich took place during the same week that world leaders met at the UN General Assembly in New York.

Prime Minister Sir Keir Starmer told the UN Security Council on Wednesday: “I’m calling for all parties to step back from the brink, to de-escalate. We need a ceasefire so this can be sorted out diplomatically.”

He added there can be “no more excuses” from Israel about humanitarian access to Gaza, and called on Hamas to release the remaining hostages.

At the Greenwich meeting, Mr Healey backed a US-led ceasefire framework and said: “There is a way that Israel can see thousands of displaced citizens returned to their homes in northern Israel, and those Lebanese can return to their homes as well.”

The Defence Secretary had earlier said: “We have held these discussions under a cloud of growing global insecurity, so in our trilateral and our bilateral meetings, we have reinforced the need to stand together against Russian aggression, towards peace in the Middle East, and steadfast behind Ukraine for as long as it takes.

“At serious times, you need serious partners, so Richard, Lloyd, we in the UK stand shoulder-to-shoulder with you, and with you we will drive the Aukus partnership from strength to strength.”