This paper proposes a velocity coordination protocol for the control of multiple unicycle agents, which aims to address two distinct scenarios in a unified manner. The former case is aggregation around a goal location, while the latter case is navigation to multiple goal locations. The same linear velocity protocol is used in both cases, but slightly different angular velocity protocols are designed to achieve either aggregation or navigation, respectively. The proposed angular velocity protocols regulate the angular velocities of the agents to reference directions imposed by vector fields which are different for aggregation and navigation. The proposed linear velocity protocol imposes directed interactions among agents in the following sense: an implicit prioritization among locally connected agents is ad-hoc decided, which results in a suitable adjustment of the linear velocities of the connected agents so that each one slows down with respect to (w.r.t.) the neighbor agent who maximizes the rate of decrease of the inter-agent distance. Simulation results with multiple unicycle agents achieving either aggregation or navigation along collision-free trajectories are provided to demonstrate the efficacy of the proposed algorithm.