A mounting element for mounting an architectural covering between two opposing mounting surfaces may include an elongate mounting member, and an extension mechanism operable between: i) a retracted state, and ii) an extended state in which the mounting element can be fastened to the architectural recess. The mounting element may also include an actuator rotatable about a rotation axis which is not parallel to the longitudinal direction, and a conversion mechanism to convert a rotation of the actuator into a translatory movement of the rotation axis along the longitudinal direction and vice versa. The extension mechanism is arranged to abut one of the opposing mounting surfaces in the extended state when the mounting element is mounted between the opposing mounting surfaces.