Democratic President Joe Biden's family has urged him to ignore calls to step aside following his disastrous debate against Republican Donald Trump.
He spent Sunday with relatives at a presidential retreat where they encouraged him to keep fighting, according to the BBC's US partner CBS News.
Anxiety has gripped sections of his party following a rambling and at times incoherent performance in Atlanta.
Polls since then suggest concerns about his age - he is 81 - have increased.
A CBS News/You