BAGHDAD (Reuters) - Some United Nations humanitarian aid staff were preparing to leave Baghdad on Wednesday for neighbouring Jordan, local U.N. staff said. They said a convoy of buses would leave U.N. headquarters in Baghdad at around 2:30 p.m. (1130 GMT). Departing staff were registering their names before leaving, while mattresses were being brought in for remaining staff to sleep in their offices. Chief U.N. arms inspector R. Butler said on Tuesday Iraq had failed to restore full cooperation with his weapons experts, prompting the United States to say that all options —including possible air strikes — remained open although no decisions had been taken.