This study presents a teleoperation system for remote control of mobile manipulators over the Internet. A bilateral control algorithm is proposed that can assure both stability and proper force reflection in the presence of non-constant delay in the communication channels between the master and the slave. The control approach in this paper is based on the time domain passivity concept and proposes a modified passivity controller to assure enhanced transparency with bounded control actions in the presence of time-varying communication delay. Transatlantic and inter-European bilateral teleoperation experiments are also reported (