President Moon Jae-in tried to reason with North Korea. Ahn Young-joon/AP South Korean President Moon Jae-in took office hoping to engage diplomatically with North Korea, but as tensions soar between the two countries, he's considering his offensive options.

Moon called for South Korea to prepare to "immediately switch to offensive operations" if North Korea makes a "provocation that crosses the line," according to NK News.

Moon told his top military officers they should "strongly push ahead with a reform of the military structure to meet [the requirements] of modern warfare so that it can immediately switch to offensive operations in case North Korea makes a provocation that crosses the line or attacks a metropolitan area," NK News notes.

Additionally, South Korea is developing a three-axis system to respond to a North Korean attack that contains preemptive strikes on North Korea's missile systems, air and missile defenses, and something called the "Korea Massive Punishment and Retaliation system."

Moon has tried to engage closely with North Korea, even going as far as suggesting the country host some of South Korea's 2018 Winter Olympics, but to no avail as of yet.

At the same time, South Korea is building up a "decapitation force" meant to kill Kim Jong Un and other key North Korean leaders while building up missile defenses. Under Moon, the country has also developed an impressive ballistic-missile fleet that can drill deep underground to hit high-value targets in bunkers.

South Korean Vice Minister of National Defense Suh Choo Suk told reporters the country hoped to have perfected its offensive and defensive plan to win a war against North Korea by the early 2020s.