This paper proposes a technique for dynamic slicing of UML architectural models. The presence of related information in diverse model parts (or fragments) makes dynamic slicing of Unified Modeling Language (UML) models a complex problem. We first extract all relevant information from a UML model specifying a software architecture into an intermediate representation, which we call a Model Dependency Graph (MDG). For a given slicing criterion, our slicing algorithm traverses the constructed MDG to identify the relevant model parts that are directly or indirectly affected during the execution of a specified scenario. One novelty of our approach is computation of dynamic slice based on the structural and behavioral (interactions only) UML models as against independently processing separate UML models, and determining the implicit interdependencies among different model elements distributed across model views. We also briefly discuss a prototype tool named Archlice, which we have developed to implement our algorithm.