The Koreas may be about the heat up with US aircraft carriers and submarines. Thomson Reuters In the aftermath of North Korea's quantum leap in nuclear strength, demonstrated by a ground-shaking sixth nuclear test, South Korea has called on the US to help "punish" Pyongyang.

“Opinions have converged that the direction which the government should take is to strengthen punishment," rather than dialogue, South Korea’s Minister of National Defense, Song Young Moo said on Monday, according to NK News.

As part of a plan to punish North Korea for its provocative intercontinental ballistic missile and nuclear tests, Moon Jae In, South Korea's president, has looked to increase the country's offensive missile capabilities and import additional missile defense batteries from the US — both of which signal a more militaristic approach to dealing with Pyongyang.

Additionally, Song told South Korea's parliament he asked Washington to regularly deploy "strategic assets" such as aircraft carriers and nuclear-powered submarines to help punish the North.

“I told them it would good to deploy assets for extended deterrence regularly in waters around the Korean peninsula,” said Song, according to NK News.

On Sunday, US Secretary of Defense Jim Mattis said the US could offer a "massive" and "overwhelming" response to North Korea's provocations, but didn't specify how.

The placement of a carrier strike group, attack submarines, and possibly nuclear-capable bombers would not only signal US resolve and show incredible force, but actually mirrors practical steps the US and South Korea would make before conflict rather than pure signaling.

This escalation may therefore heighten the risk of miscalculation in the world's most militarized area.

However in April, during joint US-South Korean military exercises, the US deployed two aircraft carriers and two submarines to the Korean Peninsula that did not demonstrably deter North Korea from progressing its missile program. Neither did the move signal any actual military intent or action.

To be clear, all US submarines run on nuclear power, and the submarines referenced by Song likely lack nuclear bombs, and instead rely on cruise missiles like other US Navy ships. However, attack submarines could serve to police or demolish North Korea's own submarine force.

SEALs and divers from SEAL Delivery Vehicle Team (SDVT) 1 swim back to the guided-missile submarine USS Michigan (SSGN 727) during an exercise for certification on SEAL delivery vehicle operations in the southern Pacific Ocean. US Navy photo by Mass Communication Specialist 3rd Class Kristopher Kirsop

Moon, a president who campaigned on reopening dialogue and engagement with North Korea, has recently turned to more militaristic approaches as North Korea's emerging thermonuclear ICBM capabilities test the US's resolve to protect South Korea.

On Sunday, in the aftermath of the nuclear test, US President Donald Trump seemed to confirm this shift.

"South Korea is finding, as I have told them, that their talk of appeasement with North Korea will not work, they only understand one thing!" Trump tweeted.