• 'We don't know who's behind this, we don't know what the motive is,' said Kirby
• The documents, which were leaked online in the last month, suggest the U.S. has a better grasp on Russia's war strategy than ally Ukraine's
• Reveal how Ukraine's S-300 air defense systems could run out of missiles and ammunition by May 2 -- potentially giving Putin the opportunity to strike by air

U.S. spies caught Russia boasting of a new alliance with the oil-rich United Arab Emirates, according to purported Pentagon documents released in a wide-ranging leak. 

Russian intelligence officers had said they had convinced the UAE 'to work together against US and UK intelligence agencies,' according to documents viewed by the Associated Press. The Emirati government on Monday dismissed any accusation that the UAE had deepened ties with Russian intelligence as 'categorically false.'   

But the report comes at a time of concerns that the U.S. is a ceding influence in the Middle East to adversaries like China and Russia. Just last month China brokered a surprise peace deal with Saudi Arabia and Iran. Other leaked documents revealed U.S. ally Egypt was prepping to ship arms to Russia. Egypt, one of the U.S.'s closest allies and a recipient of close to $100 billion in U.S. aid over the last 50 years, recently ordered around 40,000 rockets to be secretly shipped to Russia.