Kano - Nigerian forces conducted an unauthorised search of the UN's main operating base in the town of Maiduguri in the country's northeast in the early hours on Friday, the UN told AFP."Members of the Nigerian security forces entered a United Nations base for humanitarian workers in Maiduguri, northeast Nigeria, without authorisation," the UN Office for the Coordination of Humanitarian Affairs in Nigeria said by email.An internal UN memo seen by AFP suggested that the Nigerian forces may have been searching for the leader of jihadist group Boko Haram, Abubakar Shekau, after rumours spread locally that he was hiding in the compound known as the "Red Roof"."Information about Shekau's presence in the Red Roof was already being spread yesterday on social media," said the document, apparently issued by the UN's Department of Safety."At about 02:00 early this morning, Nigeria Army troops in trucks are conducting... (a) search on UN Red Roof Humanitarian camp and forced their way into the property."All UN staff in Maiduguri were ordered to work from home by the note which warned of demonstrations against the organisation and other foreign groups active in the area.A UN source told AFP such searches are illegal under international law and risk raising suspicions about the organisation's work.