The Security Council , Recalling its resolutions 1181 ( 1998 ) of 13 July 1998 , 1220 ( 1999 ) of 12 January 1999 and 1231 ( 1999 ) of 11 March 1999 and the statements of its President of 7 January 1999 ( S/PRST/1999/1 ) and 15 May 1999 ( S/PRST/1999/13 ) , Acknowledging the cooperation provided by the Economic Community of West African States ( ECOWAS ) and its Military Observer Group ( ECOMOG ) , Expressing its continued concern over the fragile situation in Sierra Leone ,