Loading Mr Morrison warned that it was "very premature" to canvass the ways Australia might back the Trump administration in the Middle East but he did not rule out options in the wake of the attacks on two oil tankers in the Gulf of Oman and Iran's decision to shoot down a US drone aircraft. Mr Morrison said "no requests were made" by Mr Trump for Australian measures but he did not rule out military or other assistance. "There's a clear objective here from the United States, which we support," he said. "And that is to get [Iran] back to the table, to get a tight ceiling of controls and conditions in place."

Asked if Australia might deploy naval vessels to escort oil tankers in the region, Mr Morrison acknowledged the Royal Australian Navy had helped protect shipping against piracy in the past. Loading "It's not unheard of to have Australian frigates in that part of the world engaged in maritime operations," he said, but he added that a "different analysis" would be needed to consider similar escorts in the current situation. In a new sign of the closeness between Mr Trump and Mr Morrison, the two not only met for dinner on Thursday night but also discussed a potential visit by the US President to Melbourne in December for the President's Cup golf tournament. The visit is regarded as a serious possibility after Mr Morrison extended a formal invitation.

Mr Morrison repeated his scepticism about the Iran nuclear deal that is meant to limit the Iranian program, given he put Australian support for the agreement up for review last October before recommitting to the agreement in December. "I've had my reservations about that arrangement but, frankly, it's better than anything else that's out there," Mr Morrison told reporters in Osaka, the host city of the summit. Mr Morrison added, however, that he and Mr Trump had a "shared understanding" of the limitations of the Iran deal. Loading Replay Replay video Play video Play video Diplomats told Reuters on Thursday that Iran was on track to exceed its cap on low-enriched uranium within days and this would breach its commitments under the 2015 deal arranged by former US president Barack Obama.

Chinese state media reported on Friday that Chinese President Xi Jinping said the Gulf region was "standing at a crossroads of war and peace" because of the tensions. Spheres of Influence Australian foreign policy experts have been largely critical of the US position on Iran, and have tended to caution the Morrison government against military involvement.

Former foreign minister Gareth Evans, who is now chancellor of the Australian National University, savaged the Trump administration's ditching of the nuclear deal. "Trump's tearing up of the JCPOA is manifestly the most wrong-headedly counterproductive and dangerous of all his foreign policy misadventures," he said, using the technical name for the nuclear deal. The Iranian supreme leader Ayatollah Ali Khamenei. Credit:AP Peter Jennings, executive director of the Australian Strategic Policy Institute, was also critical of the American position, though he said Iran had also made mistakes, with the result that both sides were in a position from which it was difficult to retreat. "They got themselves in a stalemate as a result of mutual sabre-rattling," he said. "I've not been a supporter of America's approach on this, but the Iranians are also being silly by not just sticking to the terms of the JCPOA."

He said he did not see an immediate need for Australia to take part in escorting oil tankers unless the Iranians made another threatening gesture towards commercial shipping. Loading The major risk, he said, was that Iran miscalculated in trying to provoke the US further. "The thing that I would worry about is there is a lot of missile technology in Iran," he said. "The risk of an accidental shootdown of an aircraft is high. We've seen that happen in the past and if that happened we'd be in a very serious situation." The opening day of the G20 summit saw Mr Morrison make progress on his bid to require social media companies to remove violent terrorist content, with Japan, France and Canada backing the effort to get a global agreement to impose tougher rules.