Leaked Pentagon papers predict Ukrainian's air defenses will be exhausted by MAY 23, leaving Putin free to send in fighter jets - as it's feared latest $2bn US aid won't be enough to save Zelensky's army

Ukraine's air defense systems could be depleted by the beginning of next month amid heavy fighting against Russian forces, according to what appear to be leaked Pentagon documents.

A large cache of highly classified Pentagon documents that appear to detail classified information including how Ukraine's S-300 air defense systems could run out of missiles and ammunition by May 2 at the current usage rate have appeared online in recent days.

The documents also detailed how Ukraine's air defenses protecting Ukrainian troops on the front line could be 'completely reduced' by May 23.

The Justice Department has now launched a criminal investigation into the possible release of the Top Secret documents, which mostly pertain to the state of the Ukraine war.  

An initial batch of documents labeled 'Secret' and 'Top Secret' - reportedly containing charts on the war in Ukraine as well as the strengths of different battalions - first circulated on Twitter and Russian Telegram channels last month.

And a further batch of documents of more than 100 Pentagon documents - this time also detailing US national security interests pertaining to areas including China and Israel's Mossad spy agency - was being shared on Twitter on Friday, the New York Times reported.

The authenticity of the documents is still in doubt as experts suggest they could have been altered or used as a misinformation campaign to suit Russia's agenda. They pointed to how some of the documents giving battlefield casualty estimates from Ukraine were altered to minimize Russian losses.