By Li Hongmei

The Democratic People's Republic of Korea(DPRK) announced Tuesday it was "readjusting and restarting" all facilities at its main Yongbyon nuclear complex, including a reactor mothballed in 2007.

A nuclear energy spokesman said the move was being made in line with a policy of "bolstering the nuclear armed force both in quality and quantity" as well as solving "acute" electricity shortages, the official KCNA agency reported.

In the meantime, the United States has deployed a destroyer off the South Korean coast as a measure to exert pressure on Pyongyang, a Pentagon spokesman reports.

The USS Fitzgerald provided with the Aegis tracking and guidance system was placed off the coast of South Korea on Tuesday following reports by the DPRK on Saturday that relations between the two Koreas were entering a 'state of war' and could deteriorate further, to a large-scale, or even nuclear, war.

South Korea's President Park Geun-hye has warned that Seoul will take drastic measures in response to any provocation from the North.

The South Korean authorities say they are working on 'a containment plan' that envisages a preventive strike should there be any signs of a coming attack from Pyongyang.