JERUSALEM — Doctors, patients and displaced civilians left Gaza’s largest hospital Saturday, amid competing claims over who had ordered the evacuation, which aid groups described as “complex and dangerous.” The head of al-Shifa hospital said Israel gave people one hour to evacuate, and that 120 patients and five doctors remained inside the complex, which had housed thousands of displaced people. Conditions inside the hospital for those who remained were “very difficult,” with water and electricity cut off, he added. The Israeli military denied ordering an evacuation, instead saying that it had agreed to assist evacuation efforts following requests from the hospital. Many evacuees are headed south, although Israeli forces have indicated their ground offensive may also intensify in parts of southern Gaza soon.