Port Blair, Mar 16: The Defence Secretary, Mr G Mohan Kumar, is on a three day visit to Andaman & Nicobar Command from March 14. During the visit, the Defence Secretary has been briefed on the security environment and strategic importance of the Islands. He also visited the outlying units of Andaman & Nicobar Command, including Carnic, Kamorta, Campbell Bay and Shibpur. A detailed tour of units of ANC at Port Blair was organised for the Defence Secretary on Wednesday. Later, he also interacted with the Chief Secretary, Andaman and Nicobar Administration.