Abstract: In a method of sealing a fracture (1) in a formation (2) surrounding a wellbore provided with a non-cemented perforated liner (4), a placement tool (6) is introduced into the liner and so positioned that a sealing fluid outlet (7) of the placement tool is located at the fracture (1). A placement section (8) including the sealing fluid outlet is pressed against the liner. A placement fluid is caused to flow into the fracture and controlled to obtain a desired fluid flow in an annular space (5) between the liner and the formation that is directed in downstream direction at a position upstream the fracture and that is directed in upstream direction at a position downstream the fracture. When said desired flow is obtained, sealing fluid is ejected from the sealing fluid outlet. A sealing system is furthermore disclosed.