The US top diplomat said on Thursday a major Israeli ground assault on the southern Gaza town of Rafah would be “a mistake” and “unnecessary” to defeating Hamas. His remarks underscore the further souring of relations between Israel and its principal ally, the United States. US Secretary of State Antony Blinken, on his sixth urgent mission to the Middle East since the Israel Hamas war began in October, spoke after discussing a ceasefire and Gaza’s post-conflict future with Arab diplomats. He said an “immediate, sustained ceasefire” with the release of Israeli hostages held by Hamas was urgentl…