Philippine journalist Maria Ressa, whose news site has repeatedly clashed with President Rodrigo Duterte, was arrested at her Manila office on Wednesday in what press freedom advocates branded an act of "persecution".Her detention on a charge of "cyber libel" is a dramatic escalation in government pressure bearing down on Ressa and her website Rappler, which was already facing tax evasion charges that could shut it down.It comes after Duterte has cracked down on high-profi