Hunter Biden, the son of former Vice President - and front-running Democratic presidential contender - Joe Biden, promised on Sunday to step down from his position as a board director for a Chinese investment firm this month and to cut his ties with foreign companies if his father wins the 2020 presidential election amid the controversy that has erupted over his position on company boards in Ukraine and China.

"Hunter makes the following commitment: Under a Biden Administration, Hunter will readily comply with any and all guidelines or standards a President Biden may issue to address purported conflicts of interest, or the appearance of such conflicts, including any restrictions related to overseas business interests," Biden's attorney, George Mesires, said.