WASHINGTON/CAIRO - U.S. officials sought to maintain a shaky ceasefire with Iran on Tuesday while pushing forward an operation to reopen the Strait of Hormuz, even as U.S. ally the United Arab Emirates said it suffered a new wave of Iranian missile and drone strikes.U.S. Secretary of State Marco Rubio characterized the effort to escort stranded tankers through the strait as defensive in nature, one ​day after the U.S. military said it had destroyed several Iranian small boats, as well as cruise missiles and drones.'There's no shooting unless we're shot at ‌first,' Rubio ‌told reporters at the White House, where he said the United States has achieved its objectives in its military campaign. 'Operation Epic Fury ​is concluded,' Rubio said. 'We're not cheering for an additional situation to occur.'