German public broadcaster ZDF has apologised for delays in reporting on a wave of sexual assaults blamed on men of Arab appearance amid accusations Wednesday of media self-censorship of the inflammatory issue.The rash of attacks and thefts in a New Year's Eve crowd in the western city of Cologne was only widely covered by national media early this week, after police had initially reported no major incidents.News editors of ZDF's flagship "heute" (today) evening news programme apologised on social media for not reporting on the incidents at least in its Monday evening bulletin, four days after the attacks."The news situation was clear enough. It was a mistake of the 7pm 'heute' show not to at least report the incidents," wrote deputy chief editor Elmar Thevessen on the show's Facebook page.Editors had decided to postpone the news segment to Tuesday, the day Cologne's city hall and police held a crisis meeting on the attacks, he wrote, admitting this was "a clear misjudgement".As the assaults have come to dominate German mainstream media, more women have come forward in Cologne and other cities about being groped and attacked on New Year's Eve.The number of criminal complaints in Cologne topped 100 by Wednesday.On social media, furious right-wing commentators have blamed the attacks on Chancellor Angela Merkel's government and its welcome to asylum seekers, 1.1 million of whom arrived last year.The right-wing populist Alternative for Germany party seized on the attacks as "the appalling consequences of catastrophic asylum and migration policies".A media industry website said that the ugly incidents -- and the sluggish official and media response -- played into the hands of groups such as the Islamophobic PEGIDA street movement, which claims Germany's politicians and media are colluding to mislead the public about immigration policy."Despite the world's most expensive public broadcaster, countless social media reactions and online newsrooms ... it took four long days before national media comprehensively reported on the incidents," said a commentary on the Meedia service."The initial slowness is now being used in some circles to back their claims about the 'lying press'."