­Overall more than 30,000 US troops, practically all the American military contingent in South Korea, reinforced by 3,000 troops from overseas, are taking part in joint war games with the South Korean army that started on August 20.

Despite the stated defensive nature, the annual drill known as Ulchi Freedom Guardian has predictably roused the attention of ever-wary Pyongyang.

The new North Korean leader Kim Jong-un, believed to be in his late 20s, acknowledged the great threat to his country and claimed the war games are in fact training for a preemptive nuclear attack.

The leader assured North Korean army is ready to meet "deadly blows" in “an all-out counter-offensive” in case the country’s territory is violated or even a single shell falls on North Korean soil, reports Korean Central News Agency (KCNA).

“There is a limit to our patience," warned Kim Jong-un, saying the army is only waiting for the final order to engage in a “life-and-death battle.”

The last time Washington and Seoul were flexing military muscles together was only in June. Back then Pyongyang slammed the US military for leading South Korea, Japan and the US joint drills conducted close to North Korea’s borders and called those war games a reckless provocation putting the region under the threat of a new military conflict.