(ANSA) - BELGRADE, JUN 18 - The Interior Ministers of the Baltic Sea Basin countries have signed a declaration in which Lithuania, Denmark, Estonia, Finland, Germany, Latvia, Norway, Poland, and Sweden pledge to strengthen defence cooperation, particularly against drones, unmanned aerial vehicles, and balloons. The document expresses their mutual desire to support research and development of tools to improve regional security, organise joint exercises, and promote more efficient information and knowledge exchange in the military-technological domain. (ANSA).