The proliferation of inverter-based resources (IBRs) with conventional control methods can result in significant power oscillations following disturbances. This is due to insufficient inertia and lack of damping with IBRs. To accommodate more IBRs into the system without compromising the system stability, the virtual synchronous generator (VSG) control may provide a promising solution. However, the active power control can emulate the SG rotor mechanism, the existing VSG may affect the electromechnical oscillations of power systems. This paper examines the issue with different IBR penetration scenarios on the low-frequency oscillation modes in multi-machine systems. The investigation starts with the comparisons of the impacts of IBR with VSG control integration at various locations, using eigenvalue, participation factor and nonlinear time domain simulations. Further, a comprehensive small-signal analysis is conducted to examine the changes in inter-area and local oscillation modes with an increase in IBR penetration level.