Donald Trump. Pic/AFP

US President Donald Trump today suggested paper ballot as a backup system for election amid allegations of external interference or meddling in the electoral process of a country. "One of the things we're learning is it is always good -- it's old-fashioned, but it's always good to have a paper backup system of voting. It's called paper, not highly complex computers ¿ paper," Trump told reporters at a joint news conference with the visiting Swedish Prime Minister Stefan Lofven.