All the army and people in the Democratic People's Republic of Korea (DPRK) should get ready for warfare to answer the U.S.-South Korean joint military exercise, said the Supreme Command of the Korean People's Army (KPA) on Monday.

"The men and officers of the KPA on the frontline and coastline and those standing on air guard should reliably defend the outposts of the country so as to repel at a single stroke any attempt of the aggressors to make a preemptive strike," said the command in a report carried by the official KCNA news agency.

It said that the U.S.-South Korean joint military exercise was creating tense situation on the Korean Peninsula and that a war may break out anytime.

"The units of the three services of the KPA should keep themselves fully ready to go into action in order to blow up the citadel of aggressors once the order is issued," said the report.

"All the people across the country should make a great leap forward in the general charge to build a thriving socialist nation, their hearts burning with hatred against the enemies, each holding a rifle in one hand and a hammer or a sickle in the other," it added.

The United States and South Korea started Monday their annual joint military exercises called Key Resolve/Foal Eagle, a day after the DPRK denounced the drills as a preparation for invasion and threatened to strengthen its nuclear deterrence.

The Key Resolve exercise is aimed at rehearsing the defense of South Korea in case of emergencies, while the Foal Eagle is focused on improving combined and joint operational posture between the two militaries.

According to South Korean media, about 10,000 U.S. troops and 8,000 reinforcement personnel will be participating in the joint drill for the Key Resolve exercise, and some 20,000 South Korean troops will be involved in the Foal Eagle.

The exercises are scheduled to end on March 18.