Leaked documents 'embarrassing' for US, says former security chief Sir Mark Lyall-Grant
The Pentagon described the leak as a 'very serious risk to national security' - but officials are coming under pressure to explain why such a young, low-ranking service member had access to these files.
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Speaking to Sky News, the UK's former national security adviser Sir Mark Lyall-Grant said that leaked military documents are 'concerning' and 'embarrassing' for the US.