Philippine Nobel Peace Prize winner Maria Ressa got accustomed to working against a backdrop of violence early in her career, having cut her journalistic teeth reporting from conflict zones.

But the 58-year-old said even that experience failed to prepare her for the torrent of threats, hatred and abuse she has faced from supporters of her country's authoritarian president since she co-founded investigative news site Rappler in 2011.

"There were so many hate messages...