muhammadu buhari , who won the presidential election two weeks ago , said his administration would do everything in their power to bring the students home - but said he could not promise they would ever be found .
the announcement came as a march was held through the nigerian capital of abuja to mark the first anniversary since the girls were abducted from a secondary school in chibok .
it is now a year since more than 200 schoolgirls were kidnapped by boko haram militants that