In this work, a trust-based mixed-initiative scheme for teleoperation of multiple mobile robots is developed. In the proposed scheme, the task of controlling the robots is shared between a human operator and autonomous controllers of the mobile robots. The control inputs from human and the autonomous robot controllers are dynamically blended via a computational human-to-robot trust model. Meanwhile, the haptic force feedbacks provided to the operators are also adjusted dynamically with a function of computational robot-to-human trust in order to improve human performance. The results of a preliminary study on one human-robot pair indicate that the proposed scheme can improve task performance by 31% and reduce operator workload by 23.9% compared to the pure bilateral teleoperation.