Foreign aid agencies urged Myanmar's junta Saturday to urgently clarify rules for operating in the country's cyclone-devastated areas, expressing hope tinged with cynicism after the regime promised to open its doors to the international community. Myanmar's ruling generals offered no elaboration after UN Secretary-General Ban Ki-moon's announced Friday that the junta had agreed to allow "all aid workers" into the country. The concession came after three weeks of blocking relief for cyclone survivors, and on the eve of an international donors' conference Sunday in Myanmar. "I want to be optimistic, but I'm skeptical," Lionel Rosenblatt, president emeritus of US-based Refugees International said, voicing comments echoed by relief agencies worldwide. "My overall impression is skepticism and what this actually means. The devil is going to be in the implementation." The possible breakthrough distracted attention from the junta's widely criticized decision to push ahead Saturday with a constitutional referendum in Yangon, Myanmar's largest city, and hard-hit areas of the Irrawaddy River delta.