MAPUTO, Sept 12 (Reuters) - Mozambique warned on Wednesday that high sea levels, which it described as a tsunami, were due to hit its coast between 10:00 p.m. (2000 GMT) and 1:00 a.m. and urged citizens to evacuate and head to higher ground. Mozambique's Institute of Disaster Management said the size of the tsunami was unknown but was the result of an earthquake registered earlier in Indonesia. "In view of minimising possible negative impacts, the National Emergency Operation Centre, CENOE, recommends: All the people living within 150 metres (yards) of the coastal zone must leave for higher and secure zones," the institute said in a statement.