WASHINGTON — Senior Biden administration officials sought on Tuesday to calm anger in foreign capitals over the leak of classified military and intelligence documents, but had little new information about the source of the breach or its motive.
In their first public comments since the documents appeared online several weeks ago, Defense Secretary Lloyd J. Austin III and Secretary of State Antony J. Blinken said they had spoken to their Ukrainian counterparts. Mr. Blinken also said he had spoken to unnamed American allies to “reassure them about our own commitment to safeguarding intelligence.”
Mr. Austin said he was first briefed on Thursday about the existence of the documents, which assessed the state of the war in Ukraine and the strength and capabilities of Ukrainian and Russian forces, and also included C.I.A. intelligence reports on events in foreign capitals from Cairo to Ankara to Seoul. Mr. Blinken and Mr. Austin spoke at a joint news conference at the State Department after meeting with visiting counterparts from the Philippines.
“Well, they were somewhere in the web,” Mr. Austin said of the leaked documents. “And where exactly and who had access at that point, we don’t know. We simply don’t know at this point.”
U.S. officials are investigating how the documents, numbering at least in the dozens, wound up online, whether more may yet surface — and whether a security threat exists within the Biden administration’s national security apparatus.
While acknowledging the seriousness of the leak, some officials have suggested that some of the documents may have been altered since their release online, and several foreign governments have challenged assertions the files contained about their private conversations.
Although several weeks out of date, battlefield assessments in the documents — including projections estimating when Ukraine’s air defenses might become depleted — have also raised concerns about whether the leaked information could give Russia an advantage as it prepares for a widely expected Ukrainian spring offensive.
A Guide to the Leaked Pentagon Documents
A major intelligence breach. After U.S. intelligence documents, some marked “top secret,” were found circulating on social media, questions remain about how dozens of pages from Pentagon briefings became public and how much to believe them. Here is what we know:
Asked whether the disclosure of information about the state of Ukrainian forces might affect Kyiv’s plans for such an offensive, Mr. Austin said Ukraine’s military “would not be driven by a specific plan” and expressed confidence in its ability.
Mr. Blinken added that, although the United States provides weaponry and military advice, “Ukraine makes the decisions about how it actually prosecutes the effort to regain its territory.”
Mr. Blinken said he had spoken earlier in the day to Ukraine’s foreign minister, Dmytro Kuleba, and underscored America’s support for his country against Russia’s invasion.
Mr. Austin said that he, too, had spoken on Tuesday with his counterpart, Oleksii Reznikov, the defense minister, and that Ukraine’s forces had “much of the capability that they need to continue to be successful.”
Mr. Blinken and Mr. Austin projected calm even as some foreign governments were roiling over the breach, prompting criticism of the United States for conducting surveillance of its allies and claims that the documents could not be trusted.
South Korea’s government on Tuesday described as false an intelligence report in the trove that purports to describe Seoul’s internal deliberations over whether to supply artillery shells that might end up in Ukraine.
Appearing to minimize the importance of the leak, South Korea said its defense minister, Lee Jong-sup, had spoken to Mr. Austin by phone on Tuesday morning and agreed that “quite a few of the documents in question were fabricated.”
Pentagon officials say the documents appear to be legitimate, but copies seem to have been altered in certain parts from their original format. And South Korean officials would not discuss the leaked information or what they considered to be fabricated.
Opposition lawmakers in South Korea denounced Washington for spying on the country’s national security deliberations, after the documents appeared to reveal conversations between top officials about whether to provide artillery shells to the United States that might wind up in Ukraine.
“If it is true that they have spied on us, it is a very disappointing act that undermines the South Korea-U.S. alliance, which is based on mutual trust,” Lee Jae-myung, the leader of the main opposition Democratic Party, told reporters on Tuesday. If it was true, he added, Washington should also apologize to the South Korean people.
In Cairo, Egypt’s government denied a Washington Post report, citing a leaked intelligence document the paper had obtained, which said that the country had planned to secretly produce rockets, artillery rounds and gunpowder for Russia. Egypt is one of the world’s top recipients of American aid.
John F. Kirby, a spokesman for the National Security Council, said the United States had “seen no indication that Egypt is providing lethal weaponry capabilities to Russia.”
The United Arab Emirates, another close American partner, declared as “categorically false” an assertion reported by The Associated Press, citing another document, that the Persian Gulf monarchy had agreed to deepen ties with Russian intelligence agencies and cooperate against the United States and Britain.
Among Israelis, there was only a muted reaction to the reminder that U.S. intelligence agencies spy on their country and other allies. It has long been known that Washington surveils Israeli officials. Documents leaked a decade ago by Edward Snowden, for instance, showed that the United States had intercepted the email of senior Israeli officials like Ehud Olmert, Israel’s former prime minister.
The Israeli government was also careful not to criticize the U.S. government for the latest leak. The office of the prime minister, Benjamin Netanyahu, strongly rejected the suggestion that the Mossad, Israel’s external intelligence agency, had fomented anti-government protest — but attributed the claim to the “American press,” rather than U.S. officials.
More generally, there was bemusement about the U.S. assertions about the Mossad, which raised questions about the quality of U.S. intelligence gathering and analysis.
But it was clear that even some of Washington’s closest allies were troubled by the intelligence breach. During an appearance at a think tank in Sydney, Australia’s defense chief, Angus Campbell, called the leak “serious.”
Protecting confidential information, he added, is critical to maintaining “trust and confidence” among close allies.
Reporting was contributed by Choe Sang-Hun from Seoul, Patrick Kingsley from Jerusalem, Vivian Nereim from Riyadh and Vivian Yee from Cairo.