NEW : Leader of Palestinian boycott movement welcomes Israel 's decision . Physicist Stephen Singer decides to pull out of a high - profile conference in Israel . Hawking 's move provoked fierce reaction on Twitter , including accusations of anti - Semitism . Conference organizer says academic boycott against Israel is ` ` outrageous and improper ''
NEW : Founder of Palestinian boycott movement welcomes Hawking 's decision . Physicist Stephen Hawking decides to pull out of a high-profile conference in Israel . Hawking 's move prompts fierce reaction on Twitter , including accusations of anti-Semitism . Conference organizer says academic boycott against Israel is `` outrageous and improper ''