When Nguyen Truong Chinh last visited his son Nguyen Van Chuong, a deathrow inmate in Vietnam, they cried together ahead of his imminent execution for a crime they say he did not commit. Chinh, 77, has been campaigning to free his son -- whose murder conviction came after allegations of torture -- for 16 years, and faces regular harassment in a country whose hard-line communist administration stifles dissent. US President Joe Biden visits Vietnam on Sunday pushing for closer ties as Washington seeks to reduce its reliance on China. But while Biden has often criticised Beijing's human rights record, he has largely stayed quiet on Vietnam, and campaigners are not hopeful he will use his visit to press the issue. IMAGES