Former US national security adviser John Bolton claims in his as yet unpublished memoir that President Donald Trump sought to tie hundreds of millions of dollars in aid to Ukraine to his requests for the country's leaders to investigate former Vice President Joe Biden and his son Hunter Biden, The Hill reported.

Sources familiar with Bolton's book told The New York Times on Sunday that, in it, he writes that Trump personally told him that $391 million in aid to Ukraine should be frozen until Ukrainian officials announced the investigations, including one into the Democratic National Committee.


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