Intel leak a 'serious' incident to allies

The leak of highly sensitive United States documents — many of them related to the Russia-Ukraine conflict — presents a "very serious "risk to US national security, the Pentagon said.

The breach has also created a diplomatic headache for Washington as they appear to show US spying on close allies, including South Korea and Israel. It is being investigated by the Justice Department.

A steady drip of dozens of photographs of documents have been found on Twitter, Telegram, Discord and other sites in recent days, though some may have circulated online for weeks, if not months, before they began to receive media attention last week, according to media outlets.

The documents circulating online pose "a very serious risk to national security and have the potential to spread disinformation", said Chris Meagher, assistant to the secretary of defense for public affairs, without confirming their authenticity.

According to a report by The Washington Post, senior Pentagon leadership restricted the flow of intelligence on Friday in response to the revelations, US officials said. One described the clampdown as unusually strict and said it revealed a high level of panic among Pentagon leadership.

Some US officials and their foreign allies were stunned, and occasionally infuriated, at the extraordinary range of detail the files exposed about how the US spies on friends and foes alike.

In Canberra, Angus Campbell, chief of Australia's Defense Force, said on Tuesday that the US intelligence leak was a "serious" incident, adding that the US was engaging with its partners to understand the consequences.

"The issue of maintaining security of information is critical to the development of national capability and to the trust and confidence across allies and partners," Campbell said in response to questions after a speech at the Lowy Institute.

Diplomatic headache

Meanwhile, South Korea said on Tuesday a "significant portion" of leaked US intelligence documents indicating concerns in Seoul about arms supplies to Ukraine were fake.

In a statement, South Korean President Yoon Suk-yeol's office said the country has "ironclad security "and that allegations of eavesdropping were "senseless lies".

Yoon is scheduled to travel to the US later this month on a state visit.

But US officials reportedly believe many of the documents are real.

One of the documents, obtained by Reuters, showed details about internal discussions among top South Korean officials about US pressure on Seoul to help supply weapons to Ukraine, and its policy of not doing so.

The document, which does not appear to have a date on it, said South Korea had agreed to sell artillery shells to help the US replenish its stockpiles, insisting that the "end user" should be the US military. But internally, top South Korean officials were worried that the US would divert them to Ukraine.

The report was based in part on signals intelligence, which suggests the US had been spying on South Korea, one of its most important allies in Asia, Reuters commented.

South Korea has signed major deals providing hundreds of tanks, aircraft and other weapons to NATO member Poland since the Russia-Ukraine conflict began. But Yoon said a South Korean law that forbids supplying weapons to countries engaged in conflict makes it difficult to send arms to Ukraine.

Agencies, Xinhua and Ai Heping in New York contributed to this story.