Trump suggests Biden cancer diagnosis was known earlier

US President Donald Trump appeared to fuel speculation Monday that Joe Biden's cancer diagnosis was covered up, saying he was "surprised" the public was not told about it earlier.

"I'm surprised that the public wasn't notified a long time ago," Trump told reporters, saying that it usually takes a "long time" to reach the aggressive stage of prostate cancer that Biden's office announced on Sunday.

Trump, who has long derided political rival Biden over his cognitive abilities, said Friday that he was "saddened" by the news.

On Friday, the 82-year-old Democrat — whose son Beau Biden died of cancer in 2015 — was diagnosed with the disease after he experienced urinary symptoms and a prostate nodule was found, a statement from his office said.

Biden left office in January this year as the oldest-serving US president in history. 

For much of his term, he was dogged by questions, including from Democratic voters, over his health and age and whether he could handle the office's demands.