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 a first and second annular flow barrier (8, 9) create an upstream (10), an intermediate (11) and a downstream section (12). A cross flow shunt tube (13) connects the upstream section and the downstream section, and a sealing fluid outlet (14) is arranged in the intermediate section. A placement fluid is caused to flow into the fracture and controlled to obtain a desired fluid flow in an annular space between the liner and the formation that is directed in downstream direction at a position upstream the fracture and in the 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.