A method for low-speed balancing of a rotor having at least one compressor stage blades assembly, the compressor stage blades assembly having a row of compressor blades circumferentially clamped and supported by one or more rotor discs (60,63) to form a stage of a compressor section for a gas turbine engine, and wherein the compressor stage blades assembly includes a circumferential clearance, the method comprising: - identifying a plurality of compressor blades in the compressor stage blades assembly as located blades, wherein each located blade has an angular position with respect to an axis of rotation of the compressor stage blades assembly; - maintaining the located blades in their respective angular positions within the compressor stage blades assembly such that the located blades divide the compressor stage blades assembly into a plurality of sectors, wherein each sector comprises one or more movable blades and wherein the circumferential clearance is subdivided into sectoral circumferential clearances; - circumferentially adjusting the movable blades, for each sector, such that the sectoral circumferential clearance within the sector is moved circumferentially downstream relative to the movable blades and with respect to a direction of rotation of the compressor stage blades assembly when the compressor stage blades assembly is rotated; - introducing one or more inserts in each of the sectoral circumferential clearances to maintain relative positions of the sectoral circumferential clearance and the movable blades within each sector; and characterized by - rotating the rotor up to 20% of a maximum rotational speed of the rotor, - determining a measure of unbalance for the rotor with the compressor stage blades assembly in low-speed balancing conditions; - balancing the compressor stage blades assembly; and - removing the one or more inserts after low-speed balancing has been completed. - identifying a plurality of compressor blades in the compressor stage blades assembly as located blades, wherein each located blade has an angular position with respect to an axis of rotation of the compressor stage blades assembly; - maintaining the located blades in their respective angular positions within the compressor stage blades assembly such that the located blades divide the compressor stage blades assembly into a plurality of sectors, wherein each sector comprises one or more movable blades and wherein the circumferential clearance is subdivided into sectoral circumferential clearances; - circumferentially adjusting the movable blades, for each sector, such that the sectoral circumferential clearance within the sector is moved circumferentially downstream relative to the movable blades and with respect to a direction of rotation of the compressor stage blades assembly when the compressor stage blades assembly is rotated; - introducing one or more inserts in each of the sectoral circumferential clearances to maintain relative positions of the sectoral circumferential clearance and the movable blades within each sector; and characterized by - rotating the rotor up to 20% of a maximum rotational speed of the rotor, - determining a measure of unbalance for the rotor with the compressor stage blades assembly in low-speed balancing conditions; - balancing the compressor stage blades assembly; and - removing the one or more inserts after low-speed balancing has been completed.