Seoul, 27 Jumada I,1437 AH, 07 March,2016 , SPA -- South Korean and U.S. troops began large-scale military exercises on Monday in an annual test of their defences against North Korea, which called the drills "nuclear war moves" and threatened to respond with an all-out offensive, Reuters reported. South Korea said the exercises would be the largest ever following North Korea's fourth nuclear test in January and a long-range rocket launch last month that triggered a U.N. Security Council resolution and tough new sanctions. The joint U.S. and South Korean military command said it had notified North Korea of "the non-provocative nature of this training" involving about 17,000 American troops and more than 300,000 South Koreans. The North, the Democratic People's Republic of Korea (DPRK), as it is officially known, routinely issues threats of military action in response to the annual exercises that it sees as preparation for war against it. The threat on Monday was in line with the usual rhetoric it uses to denounce the drills. -- SPA 11:17 LOCAL TIME 08:17 GMT www.spa.gov.sa/w