NEW DELHI: Army chief General Dalbir Singh is on a visit to Manipur and Assam to review the security situation, an official said on Saturday. The United Naga Council has imposed an economic blockade in the state since November 1 to denounce the creation of seven new districts from areas inhabited by Nagas in Manipur. Singh is set to retire on December 31 and will be succeeded by Lieutenant General Bipin Rawat.