<p><i>We consider the optimal control problem for a continuous system with phase constraints. It is assumed that the trajectory of the system can be divided into segments, each having a fixed set of active phase constraints. Such trajectories are typical for hybrid systems, in which transitions between segments are regarded as switchings. Applying necessary or sufficient optimality conditions for hybrid systems with intermediate constraints, we obtain a solution to the original problem with the phase constraints. Bibliography: 14 titles.</i></p>