Fears have been raised over the political future of the 58-year-old president who has already had three cancer operations since the middle of last year. More surgery will cast doubts on his political future and his "revolution" in the OPEC nation.
Venezuela's president Hugo Chavez for the first time named a successor if anything happened to him after he revealed his cancer had returned and he would undergo another operation in the coming days.
The development is a blow for his supporters, who elected him in October to a new six-year term in office. Since mid-2011 Chavez has twice said he was cured, and then had to have more surgery.
The Democratic presidential candidate may also have shown his cards on his choice of running mate.
The US president also shared a post on Twitter accusing Dr Anthony Fauci of misleading the public over hydroxychloroquine.
Fears over an impending second wave of coronavirus dominates Wednesday’s front pages.