Displaced Palestinians arrive in a truck carrying their belongings to set up shelter in a tent camp after returning to Khan Yunis in southern Gaza on May 9. AFP/Getty ImagesIn its most recent ceasefire counterproposal on Monday, Hamas demanded Israel agree upfront to an initial 12-week pause in fighting rather than six weeks, creating a major obstacle in the negotiations, three sources familiar with the deliberations tell CNN. Israeli officials are staunchly opposed to agreeing to the longer request, as they believe it would be no different than agreeing to an effective end to the war….