The purpose of this study is to explore the role of agent type and voice tone on publics' perceived organization-public relationships and behavioral intention towards an organization. Through a 2 (agent type: human vs. AI) x 2 (voice tone: conversational human vs. organizational) between-subjects experiment, the study shows that organizational messages communicated by a human agent generated significantly higher perceived control mutuality among participants in a Twitter setting than messages communicated by an AI agent. The use of conversational human voice resulted in significantly stronger relational outcomes. A significant interaction effect was found between agent type and voice tone on control mutuality. This study contributes to the public relations literature and practice by examining the potential role of AI agents in organization-public relationships and supportive behavioral intention towards an organization in the setting of Twitter.