US President Joe Biden used a highly anticipated news conference at the Nato summit on Thursday to deliver a forceful defence of his foreign and domestic policies.But the 81-year-old failed to dispel fears among senior Democrats that he is not capable of fighting November's election campaign against former president Donald Trump, as he made verbal slips that included calling Ukraine's President Volodymyr Zelensky "President Putin".

US President Joe Biden used a highly anticipated news conference at the Nato summit on Thursday to deliver a forceful defence of his foreign and domestic policies.But the 81-year-old failed to dispel fears among senior Democrats that he is not capable of fighting November's election campaign against former president Donald Trump, as he made verbal slips that included calling Ukraine's President Volodymyr Zelensky "President Putin".