The mayor of Portland, Oregon, on Monday urged U.S. officials and organizers to cancel a "Trump Free Speech Rally" and other similar events, saying they are inappropriate and could be dangerous after two men were stabbed to death on a train by a nazi skinhead as they tried to help a pair of young women targeted by an anti-Muslim tirade. Mayor Ted Wheeler said he hopes the victims will inspire "changes in the political dialogue in this country." It comes amid a wider debate in the U.S. about the First Amendment. The mayor says his main concern was participants "coming to peddle a message of hatred," saying hate speech is not protected by the Constitution. A Facebook page for the event says there would be speakers and live music." It says it will feature Kyle Chapman, who describes himself as an American nationalist and ardent supporter of President Donald Trump. The convicted robber and kidnapper cussed women on video a day before the murders and threatened to stab a train conductor.