Ukraine has already changed some of its military plans due to the leak of classified US documents, Report informs via CNN.

The news agency notes that secret Pentagon documents posted online in recent weeks show how the United States spies on both allies and adversaries, which has deeply concerned American officials who fear that the revelations could jeopardise sensitive sources and compromise important international relations.

Some of the documents, which US officials say are authentic, expose the extent of US eavesdropping on key allies, including South Korea, Israel and Ukraine.