Confidential documents detailing the US and the NATO military alliance plans to militarily assist Ukraine in launching a spring offensive against Russia have surfaced online, prompting a Pentagon probe.
The documents marked "top secret" – reportedly containing charts and details on weapons deliveries, battalion strengths and other sensitive material -- were leaked on Twitter and Telegram social media platforms, the New York Times reported on Thursday, citing Defense Department officials.
"We are aware of the reports of social media posts, and the Department is reviewing the matter," Deputy Press Secretary Sabrina Singh said in the report, suggesting that an investigation into the security breach is underway.
According to the US-based daily, one of the documents summarized the training schedules of 12 Ukraine combat brigades and added that nine of them were being trained by US and NATO forces, further pointing out that 250 tanks and more than 350 mechanized vehicles were needed for the effort.
The report stated that information in the documents also details expenditure rates for munitions under Ukraine military control, including for the HIMARS rocket systems, the US-made artillery weapon widely publicized in Western media reports as being highly effective against Russian forces.
It further noted that the documents -- at least one of which carried a "top secret" label -- were circulated on pro-Russian government channels.
The report quoted military analysts as claiming that some of the documents appear to have been altered in a “disinformation campaign” by Russia, claiming that in one document deaths of Ukrainian troopers were inflated while Russian battlefield losses were minimized.
The daily also cited officials as saying that the information in the documents is at least five weeks old, with the most recent dated March 1.
The development came amid persisting US-led efforts to send more weapons to Ukraine to further escalate the military campaign against Russia.
Washington announced a new package of military assistance worth $2.6 billion for Ukraine on Tuesday, which includes a wide variety of ammunition from Pentagon stocks, 23 million rounds of small arms ammunition and 200,000 grenades, as well as funding for more high-tech weapons.
The US has so far pledged more than $35.2 billion worth of military aid to Ukraine since February 2021, when Russia began a military operation in the former Soviet republic, insisting that it was aimed at defending the pro-Russian population in the eastern Ukrainian regions of Luhansk and Donetsk.
Russian officials have repeatedly warned Western countries against supplying weapons to Ukraine, saying it risks prolonging the already protracted war.
In January, the speaker of Russia’s parliament warned that countries supplying Ukraine with more powerful weapons risked their own destruction.
US opposes 'road map' for Ukraine's NATO membership
British daily the Financial Times reported Thursday that the US is pushing back against efforts by some European allies to offer Ukraine a “road map” to NATO membership at the alliance’s July summit, exposing divides in the West over Kiev’s postwar status.
The US, Germany and Hungary are resisting efforts from countries such as Poland and the Baltic states to offer Kiev deeper ties with NATO and clear statements of support for its future membership, the paper said.
"The divisions were made clear at a meeting of NATO foreign ministers in Brussels this week, with member state officials set to spend the next two months locked in negotiations ahead of a leaders’ summit in Vilnius in July," it said.
The negotiations come amid warnings from Ukraine’s president Volodymyr Zelensky that he will only attend the summit if presented with tangible steps towards NATO membership, such as postwar security guarantees from its members or deeper collaboration with the alliance.
Ukraine formally applied for NATO membership last year, following the outbreak of the war with Russia. So did Finland and Sweden — the former having joined the alliance earlier this week.