Australia's defence force chief has labelled possible leaks of US intelligence documents as "potentially damaging", while underscoring the need to maintain trust between allies by keeping classified information secret.
Following a speech at the Lowy Institute on Tuesday, General Angus Campbell said reports indicated the leak was "serious" as US authorities work with partners to investigate how it happened.
"The issue of maintaining the security of information is critical to the development of national capability and to the trust and confidence across allies and partners," Gen Campbell said in response to questions.
"This is potentially a damaging release of material and it is something that I would in no way wish to encourage."
Gen Campbell said as a military officer, he did not believe "all information should be free and open".
"I do believe there is a national interest in the protection of some information," he said.
The documents, which appear to be real, were published on social media sites and cover topics ranging from US support for Ukraine's defence to Middle Eastern countries' ties with Russia.
Asked about the reputational damage to the ADF over war crimes allegedly committed by Australia's special forces, Gen Campbell said the people involved needed to be supported, but the defence force also had to be held accountable.
"If we have failed as an organisation, then we need to face that," he said.
"You won't see me trying to gloss over these things, and I think that there could be some very, very uncomfortable days coming forward.
"What matters for me (are) values, behaviours, and mission of the Australian Defence Force, that's what builds reputation."
Asked about command accountability and the number of senior officers who had action taken against them, the defence force chief would not be drawn but said work was being done to implement recommendations made by war crimes investigator Justice Paul Brereton.
Gen Campbell also declined to weigh in on comments made by French President Emmanuel Macron that Europe should be careful about getting involved in crises which aren't theirs.
On how a war over Taiwan would affect Australia's national security, Gen Campbell said "anything that undermines the security, the stability and the prosperity of the Indo Pacific region ... is of interest to Australia".
Asked about the use of social media as a tool of war, Gen Campbell said the Ukrainians had been "masterful" in bringing tech-savvy people into the information fight.
"We need to understand and bring our own sense of how to ethically apply this power," he said.
Retired Australian army major general Mick Ryan said the leaks sent a "terrible message" that the US spied on "close friends" including Korea and Israel, and demonstrated they had "trouble keeping secrets".
"I'm sure the US government will want to get on top of this as quickly as it possibly can," he told ABC TV.
