New Delhi: The United States and South Korean militaries on Monday kicked off their largest joint military exercises in five years, after North Korea warned that such drills could be seen as a "declaration of war".


The military training comes amid growing threats from the North, which has conducted a series of banned weapons tests in recent months, the news agency AFP reported.


The US-South Korea exercises, called Freedom Shield, are scheduled to run for at least 10 days from Monday and will focus on the "changing security environment" due to North Korea's redoubled aggression, the allies said.


According to AFP, the Seoul military confirmed this month that it and Washington special forces were performing "Teak Knife" military drills ahead of Freedom Shield, which involved simulating precise strikes on key North Korean facilities.


All such exercises infuriate North Korea, which views them as rehearsals for an invasion.


North Korea launched two "strategic cruise missiles" from a submarine in waters off its east coast over the weekend, according to the official KCNA news agency on Monday.


The agency cited the country's "invariable stand" to confront a situation in which "the US imperialists and the South Korean puppet forces are getting ever more undisguised in their anti-DPRK military maneuvers".


"Pyongyang has military capabilities under development it wants to test anyway and likes to use Washington and Seoul's cooperation as an excuse," said Leif-Eric Easley, a professor at Ewha University in Seoul.


DPRK is the initialism for North Korea's official name, the Democratic People's Republic of Korea.


In a separate statement, North Korea's foreign ministry said, "The DPRK bitterly denounces the US vicious 'human rights' racket as the most intensive expression of its hostile policy toward the DPRK and categorically rejects it," AFP reported citing KCNA.


Washington, on the other hand, has repeatedly restated its "ironclad" commitment to defending South Korea, including using the "full range of its military capabilities, including nuclear".


Earlier in a joint news conference, the South Korean and U.S. militaries had said that they will conduct the Freedom Shield exercise, a computer-simulated command post training, from March 13 to 23 to strengthen their defense and response capabilities, and separate large-scale joint field training exercises called Warrior Shield FTX.


(With agency inputs)