WASHINGTON, Aug 2 (Reuters) - The United States ordered the evacuation of some staff and families from its embassy in Niger after military officers seized power there, the State Department said on Wednesday, even as the mission will remain open and senior leadership will continue working from there. France, the United States, Germany and Italy have troops in Niger on counterinsurgency and training missions, helping the army to fight groups linked to al Qaeda and Islamic State. See here for a complete list of exchanges and delays